EEE 34 Electrical Measureme nts Laboratory
Student Laboratory Manual © v2.0 December 2015
Electrical and Electronics Engineering Institute College of Engineering University of the Philippines !iliman
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"able of Contents "able of Contents################################################################################ Contents################################################################################ i List of $igures ################################################### ############################################################################# ################################################### ############################ ### iv Introduction ################################################### ############################################################################# ################################################### ############################ ### vi Course Syllabus ######################################################################################################## vii Class Policies ################################################### ############################################################################# ###################################################### ############################ i% & Safety Practices in the Laboratory L aboratory
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1.1 Care in handling and use of a multimeter..................................................... multimeter ..................................................... 1 1.2 Laboratory Rules and Regulations................................................................ Regulations................................................................ 2 ) Laboratory E*uipment+ "ools and Components################################## Components ################################## 3
2.1 Laboratory Eui!ment.......... Eui!ment.................... ..................... ..................... ..................... ..................... .............................. .................... " 2.1.1 #o$er %u!!ly.......... %u!!ly..................... ..................... ..................... ..................... ..................... ..................... ........................... ................. 5 2.1.2 &unction'%ignal (enerator. (enerator...................... ................................ ...................... ..................................... .......................... ) 2.1." *nalog +scillosco!e ..................... ............................... ..................... ..................... ..................... ..................... ..................... ............................................. .................................. 10 2.1., Digital +scillosco!e ..................... ............................... ..................... ..................... ..................... ..................... ..................... ............................................. .................................. 12 2.1.5 Eui!ment Calibration ..................... ............................... ..................... ..................... ..................... ..................... ..................... ............................................. .................................. 1" 2.2 Laboratory Com!onents .......................................................................................................................... 1, 2.2.1 #assive Com!onents ..................... ............................... ..................... ..................... ..................... ..................... ..................... ............................................. .................................. 1, 2.2.1.1 Resistors ..................... ................................ ..................... ..................... ...................... ..................... ..................... ......................................... .............................. 1, Resistor -alue Reading .................... ............................... ..................... ..................... ..................... ..................... ...................... ....................................... ............................ 15
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"able of Contents "able of Contents################################################################################ Contents################################################################################ i List of $igures ################################################### ############################################################################# ################################################### ############################ ### iv Introduction ################################################### ############################################################################# ################################################### ############################ ### vi Course Syllabus ######################################################################################################## vii Class Policies ################################################### ############################################################################# ###################################################### ############################ i% & Safety Practices in the Laboratory L aboratory
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1.1 Care in handling and use of a multimeter..................................................... multimeter ..................................................... 1 1.2 Laboratory Rules and Regulations................................................................ Regulations................................................................ 2 ) Laboratory E*uipment+ "ools and Components################################## Components ################################## 3
2.1 Laboratory Eui!ment.......... Eui!ment.................... ..................... ..................... ..................... ..................... .............................. .................... " 2.1.1 #o$er %u!!ly.......... %u!!ly..................... ..................... ..................... ..................... ..................... ..................... ........................... ................. 5 2.1.2 &unction'%ignal (enerator. (enerator...................... ................................ ...................... ..................................... .......................... ) 2.1." *nalog +scillosco!e ..................... ............................... ..................... ..................... ..................... ..................... ..................... ............................................. .................................. 10 2.1., Digital +scillosco!e ..................... ............................... ..................... ..................... ..................... ..................... ..................... ............................................. .................................. 12 2.1.5 Eui!ment Calibration ..................... ............................... ..................... ..................... ..................... ..................... ..................... ............................................. .................................. 1" 2.2 Laboratory Com!onents .......................................................................................................................... 1, 2.2.1 #assive Com!onents ..................... ............................... ..................... ..................... ..................... ..................... ..................... ............................................. .................................. 1, 2.2.1.1 Resistors ..................... ................................ ..................... ..................... ...................... ..................... ..................... ......................................... .............................. 1, Resistor -alue Reading .................... ............................... ..................... ..................... ..................... ..................... ...................... ....................................... ............................ 15
#otentiometer .................... ............................... ..................... ..................... ..................... ..................... ...................... ....................................... ............................ 1 2.2.1.2 Ca!acitors ..................... ................................ ..................... ..................... ...................... ..................... ..................... ......................................... .............................. 1/ 2.2.1." nductors ..................... ................................ ..................... ..................... ...................... ..................... ..................... ......................................... .............................. 1) 2.2.2 *ctive Com!onents ..................... ............................... ..................... ..................... ..................... ..................... ..................... ............................................. .................................. 1 2." Laboratory ools .......................................................................................................................... 20 2.".1 3ultimeter ..................... ............................... ..................... ..................... ..................... ..................... ..................... ............................................. .................................. 20 2.".1.1 *nalog 3ultimeter ..................... ................................ ..................... ..................... ...................... ..................... ..................... ......................................... .............................. 21 4sing the 3ultimeter to 3easure -oltage Current and Resistance .................... ............................... ..................... ..................... ..................... ..................... ...................... ....................................... ............................ 22 6ero7ing the 3eter %cale .................... ............................... ..................... ..................... ..................... ..................... ...................... ....................................... ............................ 2, Connectivity'Continuity est .................... ............................... ..................... ..................... ..................... ..................... ...................... ....................................... ............................ 2, 2.".1.2 Digital 3ultimeter 25 2.".2 D8*rsonval (alvanometer or 1m* 3ovement ..................... ............................... ..................... ..................... ..................... ..................... ..................... ............................................. .................................. 2/ 2."." #rotoboard'9readboard ..................... ............................... ..................... ..................... ..................... ..................... ..................... ............................................. .................................. 2) 2.".".1 #rotoboard :iring ..................... ................................ ..................... ..................... ...................... ..................... ..................... ......................................... .............................. 2 2.".".2 Debugging'roubleshooting Circuits ;11< ..................... ................................ ..................... ..................... ...................... ..................... ..................... ......................................... .............................. "0
ii 3 Electrical Measurements ######################################################################################################## 3)
".1 heory and #ractice .......................................................................................................................... "" ".2 Error and Linearity .......................................................................................................................... ", ".2.1 Error ...................................................................................................................... ", ".2.2 Linearity ...................................................................................................................... ", "." *ccuracy and #recision .......................................................................................................................... " "., Circuit7Level *nalysis of the 3ultimeter .......................................................................................................................... "/ ".,.1 #ractical #o$er %u!!ly ...................................................................................................................... "/ ".,.2 Characteristic of the 1m* movement (alvanometer %cale ...................................................................................................................... ") ".,." DC *mmeter ...................................................................................................................... " ".,., DC -oltmeter ...................................................................................................................... ,1 ".,.5 +hmmeter ...................................................................................................................... ," 4 E%periments ######################################################################################################## 4,
E=!eriment 0> 9asic 3easurements .......................................................................................................................... ,/ E=!eriment 1> Debugging Circuits .......................................................................................................................... 52 E=!eriment 2> DC 3easurements ?Current@ .......................................................................................................................... 5/ E=!eriment "> DC 3easurements ?-oltage@
.......................................................................................................................... 1 E=!eriment ,> Resistance 3easurements .......................................................................................................................... E=!eriment 57a> ntroduction to +scillosco!es ?*nalog@ .......................................................................................................................... /1 E=!eriment 57d> ntroduction to +scillosco!es ?Digital@ .......................................................................................................................... / E=!eriment > *C Detection A Diodes .......................................................................................................................... )/ E=!eriment /> *C *nalysis A RLC Circuits .......................................................................................................................... , E=!eriment )> ransducers and +!erational *m!liBers .......................................................................................................................... ) , !ocumentation ###################################################################################################### &-&
5.1 Documentation (uidelines ........................................................................................................................ 101 5.1.1 echnical Develo!ment ..................................................................................................................... 101 5.1.2 #a!er &ormat and *!!earance ..................................................................................................................... 101 5.2 +nline %ubmission (uidelines ........................................................................................................................ 102 . Pro/ect ###################################################################################################### &-3
.1 #roect (uidelines ........................................................................................................................ 10" .1.1 #roect #ro!osal ..................................................................................................................... 10" .1.2 #roect esting and Construction ..................................................................................................................... 10, .1." #roect Documentation ..................................................................................................................... 10, .1., #roect #resentation
..................................................................................................................... 10, .1.5 Criteria for (rading ..................................................................................................................... 105 .2 &reuently *sed uestions ?&*s@ ........................................................................................................................ 105 0eferences ###################################################################################################### &-1
iii *!!endi= *> %am!le EEE #a!er for *, #age %iFe ........................................................................................................................... 10 *!!endi= 9> %ome Gotes from ransducer Datasheets ........................................................................................................................... 110 *!!endi= C> %ome Gotes from +!erational *m!liBer ?+!7*m!@ Datasheets ........................................................................................................................... 112 *!!endi= D> *vailable Com!onents in nstruments RoomH ........................................................................................................................... 11"
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List of $igures &igure 1. Connecting $ires..................................................................................... " &igure 2. *lligator cli!s........................................................................................... , &igure ". Controlled7voltage su!!ly ?left@ and controlled7current su!!ly ?right@ modes.................................................................................................................... 5 &igure ,. Controlled7voltage su!!ly mode $ith ).)- used to !o$er7u! a sim!le circuit..................................................................................................................... &igure 5. ri!le out!ut !o$er su!!ly unit ?#%4@. .................................................... &igure . #rogrammable DC #o$er %u!!ly ?ri!le +ut!ut@ ..................................... / &igure /. %ig7gen set at 1.0001IF and 10-!ea7to7!ea ?-!!@ level................... ) &igure ). %ig7gen !robe. he circuit7end are red and blac alligator cli!s $hile the sig7gen end is a 9GC connector.................................................................................................... ) &igure . *nalog oscillosco!e self7calibration using built7in 2-!! 1IF suare7 $ave signal. ............................................................................................................................. 10 &igure 10. +scillosco!e !robes. ............................................................................................................................. 11 &igure 11. Digital +scillosco!e ............................................................................................................................. 12 &igure 12. Resistor ty!es based on com!osition material and tolerance level. ;5< ............................................................................................................................. 1, &igure 1". Resistor Color Code. ;5< ............................................................................................................................. 15 &igure 1,. #otentiometer> actual ?left@ electrical model ?middle@ and usual electrical symbols ?right@. ;< ............................................................................................................................. 1 &igure 15. DiJerent ty!es of ca!acitors both non7!olar and !olar. ;/< ............................................................................................................................. 1/ &igure 1. . Ceramic ca!acitor value reading. ;)< ............................................................................................................................. 1) &igure 1/. DiJerent ty!es of inductors. ;< ............................................................................................................................. 1) &igure 1). *nalog multimeters. ............................................................................................................................. 21 &igure 1. *nalog multimeter selector nob. ;2< ............................................................................................................................. 22
&igure 20. *nalog multimeter calibration scale. ;"< ............................................................................................................................. 2" &igure 21. 6ero7ing the meter scale. ;,< ............................................................................................................................. 2, &igure 22. Iand7held digital multimeters. ............................................................................................................................. 25 &igure 2". 9ench digital multimeter. ............................................................................................................................. 2 &igure 2,. 1m* movement. ............................................................................................................................. 2/ &igure 25. #rotoboard. ;10< ............................................................................................................................. 2) &igure 2. #rotoboard $iring of t$o com!le= circuits> messy $iring ?left@ and clean $iring ?right@. ;10< ............................................................................................................................. 2 &igure 2/. #ID Comics> Debugging. ;12< ............................................................................................................................. "1 &igure 2). ?a@ %im!le resistive circuit ?b@ ideal voltmeter and ?c@ !ractical voltmeter ............................................................................................................................. "" &igure 2. n!ut7out!ut relationshi! sho$ing linearity. ............................................................................................................................. ", &igure "0. DiJerence bet$een accuracy and !recision. ;1"< ............................................................................................................................. " &igure "1. #ractical voltage source ?left@ and !ractical current source ?right@. ;1,< ............................................................................................................................. "/ &igure "2. 1m* movement inside structure ?left@ and its electrical symbol ?right@. ;15< ............................................................................................................................. ") &igure "". 3easuring current using the galvanometer as the ammeter. ............................................................................................................................. " &igure ",. E=tending the range of the ammeter. ............................................................................................................................. ,0 &igure "5. DC -oltmeter structure using 1m* movement. ............................................................................................................................. ,1 &igure ". 3easuring voltage using the galvanometer $ith a series resistor as the voltmeter. .. ,1 &igure "/. +hmmeter structure using 1m* movement. ............................................................................................................................. ,"
&igure "). 3easuring the resistance of an unno$n resistor using analog ohmmeter. ............................................................................................................................. ,, &igure 9. 1. y!ical res!onse curve A tem!erature versus resistance of 4E,,/ GC hermistor. 110 111 &igure 9. ". Resistance as a function of illumination. ........................................................................................................................... 111 &igure 9. 2. 9asic Centigrade tem!erature sensor ?K2
K 150@.
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&igure C. 1. L3/,1 o!erational am!liBer !in7outs. ........................................................................................................................... 112 &igure C. 2. L&"5" o!erational am!liBer !in7outs. ........................................................................................................................... 112
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Introduction aing electrical measurements is an essential sill that every engineer must learn and master. :ithout it $e $ill not no$ ho$ to evaluate and im!rove things. his is an essential !art that someho$ sha!es the ind of technology $e have today A further on $hat it $ould be lie tomorro$. Io$ever taing electrical measurements is not a sim!le read-and-record tas. his sill reuires that a student must be able to determine ?and hence a!!ly@> a. $hat ind of measurements or e=!eriments are best suited for a !articular a!!licationM b. $hich tool or set of tools are essential to accom!lish such tasM c. ho$ to analyFe verify and inter!ret or Nmae7sense8 of the acuired data andM d. ho$ to !ro!erly re!ort data such that others can understand them $ithout vagueness ambiguity and'or confusion. EEE ", ?Electrical 3easurements Laboratory@ is the gate$ay of students in familiariFing $ith the common eui!ment com!onents and tools being used in EEE instructional laboratories
A $hile observing safety !ractices. he main goal of the course is to !rovide students a further understanding of the theoretical conce!ts gained in EEE "1 ?ntroduction to Electrical and Electronics Engineering@ and currently learning in EEE "" ?Electric Circuit heory@ by im!lementing actual circuits and investigating the !ractical issues in measurements through hands7on e=!eriments. his student laboratory manual aims to !rovide the students ?as $ell as laboratory instructors@ a com!lete uniform and coherent document in achieving the course goals and obectives. his $ill also give laboratory instructors more time to focus in teaching and guiding the students $ith the hands7on rather than !roviding the OoPineQ no$ledge. he delivery of the content ho$ever still de!ends on the !rerogative of the instructor. n summary this manual aims to !resent EEE ", in an ecient and eJective $ay. 3y sincerest gratitude to %iegfred 9alon *drian %alces and !revious S current EEE ", instructors $hose $or built the foundation of and hence further im!roved this courseM to Taybie de (uFman for bringing u! the conce!t of $riting this laboratory manual A and in his contribution in !roviding some of the content. &inally $ish to than my !ast EEE ", students for ins!iring me to $rite this laboratory manual.
Engr# Patth 0ic2 L# 0amire Electrical and Electronics Engineering nstitute 4niversity of the #hili!!ines A Diliman
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Course Syllabus EEE 34 Electrical Measurements Laboratory I#
Credits 1.0
II#
unit laboratory
Prere*uisites Co5re*uisites EEE "1 ?!rereuisite@ EEE "" ?co7reuisite@
III#
Schedule 1 meeting'$ee " hours'meeting
I6#
Course !escription Laboratory !rocedures and !ractice data collection and analysis laboratory documentation standard electric instruments and circuits basic electric circuit behaviour transducers.
6#
Course 7oals a. o understand conce!ts and !ractical issues in electrical measurement b. o gain no$ledge of the o!eration and interaction of various electric com!onents and transducers in electrical circuits and measurement systems. c. o develo! sills in !ro!er laboratory !rocedures and !ractice data collection and analysis and laboratory documentation d. o familiariFe the use of analog and digital electrical measurement eui!ment such as oscillosco!es multimeters and signal generators
6I#
Course 8b/ectives a. %et7u! and characteriFe sim!le electrical circuits and electrical measurement systems. b. Describe the behaviour of a circuit as electrical characteristics of an electrical com!onent or transducer are changed. c. Demonstrate safe and !ro!er laboratory sills and create !ro!erly formatted and meaningful laboratory documentation d. ncor!orate the use of electrical measurement eui!ment in the analysis and characteriFation of sim!le electrical circuits.
6II#
Course Schedule and Content
Session 9
0
1
27"
Session ob/ectives
Clarify class !olicies and note im!ortant ideas about the courseM demonstrate !ro!er use of laboratory facilities and eui!mentM Em!hasiFe safety !ractice in the laboratory ntroduce !assive com!onents used in EEE A resistors ca!acitors and inductors. #erform basic electrical measurements #erform diJerent methods of maing DC voltage and current measurementM identify $hen each method is
"opic
%yllabus Discussion Laboratory eui!ment !rocedures and !ractice %afety uiF Electronic com!onent value reading 9asic Electrical 3easurements DC 3easurements
,
a!!licableM s!ecify the degree of accuracy of any measurement made and identify the main causes of error. #erform diJerent methods of measuring resistanceM identify $hen each method is a!!licableM %!ecify the degree of accuracy of any measurement made and identify the main causes of error.
Resistance 3easurements
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*ssess basic laboratory instrumentation and
1st #ractical E=am ?&or to!ics covered in meetings 1 to ,@
measurement sillsM revie$ and a!!ly learned conce!ts and sills from the Brst t$o e=!eriments. Describe the o!eration of a triggered s$ee! +scillosco!e &undamentals oscillosco!eM mae basic measurements using an oscillosco!eM s!ecify the degree of accuracy of any measurement made and identify the main causes of error. E=!erimentally determine the voltage across a *C 3easurements ?#o$er conducting diodeM e=!lain conce!ts involved in R3% #ea7to7!ea -oltage maing !ea and R3% voltage measurements of *C #hasor #o$er factor@ signalsM account errors introduced by non7ideal characteristics of the diode on the measurements made. Revie$ and a!!ly learned conce!ts and sills 2nd #ractical E=am ?for from the to!ics e=!eriments " and ,. covered in meetings 7@ #erform measurements using the basic and Digital nstrumentation advanced ?%ignal features of digital instrumentation and (enerator Digital measurement 3ultimeter@ eui!mentM enumerate the beneBts and dra$bacs of digital measurement eui!ment as com!ared to analog measurement eui!ment. Determine the inductance or ca!acitance of a nductance and device Ca!acitance using in!ut7out!ut time7domain $aveformsM 3easurements s!ecify the degree of accuracy of identify the main causes of error. Describe the o!eration and electrical ransducers and sensors characteristics of commonly7used transducers and sensorsM !erform measurements using transducers sensors and electrical measurement circuitsM account errors introduced by non7ideal characteristics of the transducers and sensors on the measurements made. ransducer #roect #roect #resentation
7/
)7
10 11
12
1"
1,715 1
6III# 0eferences
Larry D. Tones S *. &oster Chin Electronic nstruments and 3easurements 2nd Edition #rentice7Iall 11. Tose!h Carr Elements of Electronic nstrumentation and 3easurements "rd Edition #rentice7Iall 1.
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*lbert D. Ielfric and :illiam D. Coo!er. 3odern Electronic nstrumentation and 3easurement echniues 2nd Edition #rentice7Iall 10. *lan %. 3orris #rinci!les of 3easurement and nstrumentation 2nd Edition #rentice7Iall 1".
0e*uirements %afety and :or Ethics Laboratory Re!orts #ractical E=ams #roect
:#
10U ,5U "0U 15U
7rading System ;1002< ?2))< ?))),< ?),)0< ?)0/<
1.00 1.25 1.50 1./5 2.00
?/2)< ?),< ?,0< ?00<
2.50 2./5 ".00 5.00 No 4.00 nor INC.
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Class Policies Laboratory Instructor Game> +ce Room> Email *ddress> Consultation Iours>
VnameW Vfaculty roomW Vemail addressW V9*W
"he follo;ing may change depending on the prerogative of respective laboratory instructor< a. &or every laboratory tas a student must form'oin a grou! ?ma=imum of " de!ending on available $orstations@. (rou!ings ?either random or choose7your7o$n@ may vary from tas to tas. t is the res!onsibility of the student to acuaint $ith his'her grou!7 mates at the start of every e=!eriment. 4# students are e=!ected to be versatile and thus can $or $ith all ind of team7mates. b. #re7Laboratory ?=Pre-Lab”@ re!ort must be submitted in class before any corres!onding e=!eriment. %e!arate Pre-Lab sheets are available in this manual. * student $ill >8" be allo$ed to do the e=!eriment in failure to submit the PreLab re!ort. Co!ied $or is intellectual dishonesty and $ill never be acce!ted. c. Each grou!H must submit a laboratory re!ort ?=Post-Lab”@ that summariFes the e=!eriment and ans;ers the guide *uestions in the e%periment through the results obtained. &urther observation and in7de!th analysis $ill earn additional merit. he laboratory re!ort must be submitted ?in5print@ ?not necessarily coloured@ t;o ;ee2s after the e%periment ?due "0 minutes from ocial start of class@. Late !a!ers $ill automatically receive a Fero grade. he Post-Lab re!ort must be in EEE !a!er format ?a sam!le tem!late is given in *!!endi= 9@. d. &or any submitted re!ort never forget to cite reference's if there is'are any. &ailure to !ro!erly document and acno$ledge an e=isting $or is considered intellectual mal!ractice. e. %tudent's arriving "0 minutes late $ill be considered absent and $ill receive no grade for the laboratory re!orts on the e=!eriment for that day. Io$ever for the love of learning he'she'they can still oin his'her'their grou!7mates in !erforming the e=!eriment. Go mae7u! class for une=cused absence's. f. %tudent's incurring more than three ?"@ absences $ill be advised to dro! the course or $ill be given a failing grade if the dro!!ing !eriod has la!sed. g. :or ethics inside the laboratory must be observed. Go !hones or gadgets. Io$ever they can be used shortly for documentation !ur!oses. Clean u! your $or!lace $hen done. 3ae sure to turn oJ all eui!ment and measuring tools'devices before leaving. Com!onents used must be returned !ro!erly. h. Class standing $ill be available online at the middle of the semester. i. n case of a class sus!ension $ait for announcements from the laboratory instructor regarding deadlines and ho$ the schedule of activities $ill be changed. *lso inform the laboratory instructor for schedule conXicts ?es!. 3onday classes@ $ith scheduled de!artmental e=ams as early as !ossible. . *ll students should be a$are of the safety !ractices as $ell as the rules and regulations im!osed in the laboratory. hese are available in the succeeding sections. Initial re*uirements< 1. Toin our &aceboo grou!'4-Le section $ith name YYYYYYYYYYYYY and !assey YYYYYYYYYYYYYY. *nnouncements and other broadcast message $ill be !osted here. 2. *ccom!lish a softco!y version of the traditional student inde= card A the %tudent nformation Card ?%C@. * sam!le tem!late $ith guidelines can be found in our online grou!.
H(rading of course reuirements to be submitted by grou! is GDE#EGDEG of any issue internal to the grou! concerned ?e.g. student A did not !artici!ate !re!aring this'that
student B is going to be late but the Bnal re!ort is $ith him'her etc.@. *lthough a !ortion of grade is evaluated !er grou! the maority still is individual assessment.
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& Safety Practices in the '&( Laboratory %afety is al$ays the biggest concern $hen $oring in a laboratory !articularly $hen dealing $ith electricity. his concern covers not only valuable research $or and eui!ment but e=tends to the lives of the !eo!le as $ell. 3ore often than not accidents ha!!en due to carelessness and im!ro!er handling or use of eui!ment. 3ost accidents can be avoided through !ro!er safety !recautions and common sense. Iere are a fe$ of them. 1. Do G+ touch anything that you are unfamiliar $ith. 2. &ollo$ instructions. hey are there for a reason. ". 9e careful and do G+ hurry. *l$ays $atch $here you are going and $hat you come into contact $ith. ,. Do G+ eat or drin in the laboratory. ?G+ &++D or DRGZ% allo$ed inside the lab@ [ou do not $ant to ingest small !arts !otentially haFardous chemicals and other materials. %!ills can also cause eui!ment and electrical $iring to short circuit and catch Bre. 5. :ear !ro!er clothing. t is advisable to $ear closed rubber shoes to avoid body contact to ground $hen dealing $ith electricity. hose $ho $ear contact lenses may be more sensitive to the fumes and heat. . Do G+ $or on electrical eui!ment $hen you are com!letely alone and never $or on OliveQ eui!ment $hen you are tired. /. 4nless it is im!ossible to avoid do not $or on live circuits. *l$ays un!lug'turn oJ devices before $oring on them. f you are $oring on $iring turn oJ all !o$er. urn oJ the circuit breaer or fuse 7 or master s$itch if necessary 7 and mae sure !o$er cannot be restored accidentally. ). Gever touch electrical eui!ment $hile standing on a dam! or metal Xoor. *lso never handle electrical eui!ment $hen you or the eui!ment is $et or dam!. . (round all high7voltage !oints 7 remember a ca!acitor can store a charge that can ill you. Do G+ handle electrical eui!ment that is not grounded and never remove eui!ment grounds. 10. *bove all communicate. Do not be afraid to as uestions if you are not sure about $hat you are doing. * lot of damage can result from incorrect !rocedures. *lso re!ort anything out of the ordinary !articularly frayed $ires e=cessive heating s!ars and smoe that can lead to a !otentially dangerous situation. Remember it is better to be safe than sorry. Additional Precautions>
1. D+ G+ +4CI the !o$er !lugs connecting the table outlets to the Xoor outlets A doing so riss being subected to an electric shoc and !ossibly death. 2. ae note of the limitations of the instruments and com!onents ?!o$er current or voltage@. 3ae sure that you do not subect com!onents and instruments to values of voltage and currents that can destroy them. ". :hen measuring voltage it is good !ractice to use ust one hand. Tust cli! one terminal to one node and hold the other at the insulated !art of the test !robe GE-ER on the metal ti!. ,. n measuring current shut !o$er oJ before breaing the circuit. nsert the ammeter before turning the !o$er on. 5. Re!ort damages as soon as !ossible.
&#& Care in handling and use of a multimeter 9efore inserting the meter into the circuit be certain that>
he meter s$itch or s$itches have been set to the !ro!er measurement function.
he meter s$itch or s$itches have been Brst set to the highest voltage or current range in measuring an unno$n voltage or current. his $ill reduce the !ossibility of meter overload and damage. he meter test leads have been !lugged into the !ro!er test acs.
he !olarity is being observed in measuring voltage or current. #o$er is disconnected before resistance is measured in the circuit
n measuring current the circuit has been broen so that the meter may be inserted in series $ith the circuit he voltage or current to be measured does not e=ceed the range or ca!abilities of the meter. BA0>I>7> Do not allo$ the meter to be connected for a !rolonged time $hen the needle goes to the left
of Fero or beyond the full7scale deXection.
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&#) Laboratory 0ules and 0egulations (Approved by the UP-EEEI Facuty-!n-char"e o# ALab$BELab as o# December 2015 %
1. %tudents are e=!ected to conduct themselves in a !rofessional and courteous manner $hen inside the laboratory. 2. D+ G+ 9RG( G any Xuid or Xammable'e=!losive materials inside the laboratory. ". &ood and drins are not allo$ed inside the laboratory. ,. 9ags and other !ersonal items must be !laced in designated areas during laboratory classes. 5. &loor $all and table electrical outlets in the laboratory should be used and handled carefully. Re!ort any damaged or broen utility outlets. . 9e a$are of !o$er ratings current and voltage reuirements $arnings and s!ecial instructions on each laboratory e=ercises. /. -*GD*L%3 is not tolerated. his includes removal of eui!ment tags S labels $riting on $alls cabinets tables chairs etc. ). * student shall be held liable for eui!ment or damaged due to abuse misuse negligence or disregard of basic electronics no$7ho$. gnorance of !ro!er eui!ment handling shall not be acce!ted as an e=cuse. Re!lacement or re!air e=!enses shall be demanded to liable student $ho inXicted damaged to 4# #ro!erty. . *s in the case of loss or broen electronic com!onents students are held res!onsible to re!lace the items. 10.Eui!ment that is not yet'anymore in use should be turned oJ and'or un!lugged. 11.Laboratory eui!ment may not be taen else$here. *ll laboratory $or done $ith *Lab'9ELab eui!ment should be done inside the *Lab'9ELab. 12.CLE*GLGE%% and +RDERLGE%% of the laboratory should al$ays be maintained. %tudents are e=!ected to clean u! their $or areas after the class and thro$ a$ay $aste materials in the trash bins !rovided. 1".Gon7students and other students not enrolled in a class are not allo$ed inside the laboratory 1,.%tudents $ith laboratory classes at other time slots may oin a laboratory class $ith the consent of the instructor holding the class. he Brst !riority to use the Laboratory is given to students $ho are in regularly scheduled class. 15.%tudents may not use the laboratory eui!ment'room $ithout the su!ervision of his'her instructor or !ermission from the laboratory faculty7 in7charge'technician. 1.+nly 4# D $ill be acce!ted in borro$ing laboratory eui!ment and com!onents. %tudents $ho fail to return the eui!ment 'com!onents on time $ill not be allo$ed to borro$ again.
-iolation of the aforementioned rules and regulations shall be met $ith !unishments ranging from but not limited to grade deductions a failing grade sus!ension or e=!ulsion from the university or a combination thereof. Re!lacement of damaged eui!ment or other !ro!erties shall also be demanded of the violator.
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) Laboratory E*uipment+ "ools and Components his cha!ter gives the student a uic overvie$ on the common eui!ment tools and com!onents being used in EEE laboratories. he goal of this cha!ter is for students to gain familiarity on ho$ these things $or and loo lie. Io$ever the o!eration and !ro!er usage should be demonstrated in class. he tools and eui!ment include the multimeters !o$er su!!lies function or signal generator oscillosco!e 1m* movement and the !rotoboard. Gote ho$ever that the images sho$n here might not be the same actual tools or eui!ment that $e are going to use in our laboratory ?a diJerent brand or version might be available@. Gonetheless their usage and o!eration should be similar.
)#& Laboratory E*uipment Laboratory eui!ment are electronic a!!aratus $hich are intended for s!eciBc !ur!ose or a!!lication. hese are bench7ty!e a!!aratus that should stay on the station $here these are designated. he cost for each ranges from tens to hundreds of thousand #I# that is $hy safe and !ro!er usage must al$ays be observed. n EEE laboratories $e can Bnd various laboratory eui!ment de!ending on the $or or needs of such res!ective laboratories. &or EEE ", $e $ill use the ?a@ !o$er su!!ly ?b@ function'signal generator and ?c@ oscillosco!es. he !o$er su!!ly as the name im!lies generates or su!!lies !o$er ?usually DC@ to the circuit to be connected to it. he function'signal generator on the other hand also su!!lies !o$er but in *C form. Lastly oscillosco!es are used to ca!ture and dis!lay signals usually *C signals and in time7domain analysis. 9efore $e !roceed $ith the discussion it is useful to become clear on the ty!es of connectors $e $ill commonly use. %ho$n in &igure 1 are connecting $ires A the sim!lest and uicest $ay to connect com!onents and circuits. hese are basically conducting $ires usually of made u! of chea! metal $ra!!ed $ith coloured insulator. he use of colors hel!s in deBning nodes as it conveniently a!!lies to all in constructing circuits.
F!"ure &. Connect!n" '!res
, *nother common connectors are called alligator cli!s sho$n in &igure 2 as the conducting cli! resembles the mouth of an alligator. he terminologies here are uite intuitive A because the thining'analysis Ndiculty8 must not de!end on the identiBcation of each tools or eui!ment.
F!"ure . A!"ator c!ps
*lligator cli!s are ust lie connecting $ires e=ce!t that the end's is'are of the form of alligator cli!'s ?ugh\ cannot Bnd another term for it@. Connecting $ires alligator cli!s and other ty!es of connectors re!resent the so!d !nes that $e use to construct our circuits in theory. &rom this !oint on the reader must be able to distinguish alligator cli!s easily from other ty!es of to-be-d!scussed connectors.
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)#&#& Po;er Supply n most EEE laboratory courses $e $ill only deal $ith voltage su!!lies. Current su!!lies on the other hand is seldom used unless the $or is on !o$er electronics. Let us e=amine the single out!ut DC !o$er su!!ly sho$n in the Bgure belo$.
F!"ure ). Controed-vota"e suppy (e#t% and controed-current suppy (r!"ht% *odes.
he adust nobs set the desired level of voltage or current. he maor nobs are for coarse adustments $hile the N&GE8 tunes in Bner granularity useful in setting su!!ly $ith high accuracy. %ho$n on left of &igure " is the controedvota"e suppy *ode ?loo closely A green LED is lit on OC-Q@ $hile on the right it is in controlled7current su!!ly ?green LED is lit on OCCQ@. hroughout the course $e $ill only use voltage su!!lies so it is necessary that our !o$er su!!ly is in C6 mode. o achieve this turn the Ncurrent adust nob8 fully cloc$ise and the C- LED should be lit. :hile on this mode be e=tra careful that the red and blac alligator cli!s do not get shorted. +ther$ise the su!!ly $ill force itself to go in CC mode ?$ith a Nticing8 sound@. %uch short7circuit event is harmful not only to your circuit com!onents but also to one8s !ersonal health. Remember that it is not the voltage but the current that could be fatal. he color code again is intuitive and $e can see is also uniform A red for positive and blac2 for negative. Gote that the (GD !ort in the eui!ment is >8" the ground of the to-be-constructed-c!rcu!t but the ground of the eui!ment itself. he students are the ones deciding'designing $hich node is the ground for their circuits. &or e=am!le su!!ose $e have set 5.0- as sho$n on the left of &igure ". his voltage level indicates a potential diference of 5.0- bet$een the !ositive and negative !orts ?i.e. from the negative !ort there is a voltage rise of 5.0- going to
the !ositive !ort@. :e can therefore use either !ort as the OreferenceQ or the ground of the to-be-constructed c!rcu!t . f the blac cli! is used as ground'reference then the red cli! serves as !ositive ?K@ 5.0-. f the red cli! is used as ground'reference instead then the blac cli! serves as negative ?7@ 5.0-. he students should not be confused $ith this conce!t es!ecially if $e go into a!!lications reuiring bi!olar voltage su!!lies ?e.g. K'75- for o!erational am!liBers@.
F!"ure 4. Controed-vota"e suppy *ode '!th +.+, used to po'er-up a s!*pe c!rcu!t.
n &igure , the !o$er su!!ly is !roviding the circuit $ith ).)-. Io$ever $hile the !o$er su!!ly is in C- mode it also indicates a current of 0.01*. s there something $rong here] *ctually there is none. he !o$er su!!ly also indicates ho$ much current $ith the set voltage level at C- mode the circuit is dra$ing. f $e have set to ).)- and the circuit is dra$ing 0.01* ho$ much !o$er ?in :atts@ does the circuit consume] Lastly notice the !osition of the decimal !oint both in current and voltage. %u!!ose $e target to get a voltage level of 0.1-. %ince the su!!ly only dis!lays u! to tenths digit if it dis!lays 0.1- then $e are not certain if $e have 0.1 000or 0.1-. herefore !erha!s $e can adust from 0.0 - and sto! turning the nob ust before it dis!lays 0.1000-. Does that mae sense] Looing for$ard imagine if all grou!s in one class uses single out!ut DC su!!ly and a grou! needs at least 2 voltage levels each. hen the $orstations $ill be Blled $ith a bunch of DC su!!lies. :ith that the laboratory also has tri!le out!ut !o$er su!!ly units ?#%4@. *n actual !hoto is sho$n in &igure 5 .
F!"ure . r!pe output po'er suppy un!t (P/U%.
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n this DC su!!ly ?see &igure 5@ +ut!ut * has B=ed 5.0- su!!ly ?1000m* overload limit@ $hile +ut!uts 9 and C ?250m* overload limit@ are adustable from 0- to 20-. he "avano*eter scae indicates the voltage'current level of +ut!ut 9 or C de!ending on the selection s$itch found at the bottom. he interface !orts here ho$ever is a bit diJerent $ith that of the single out!ut DC su!!ly. *lligator cli!s ?for both ends@ can be Ncli!!ed8 on the metallic !orts on one end and the other to your circuit. n any case it is al$ays a safe !ractice to set the desired voltage level Brst in IS8LA"I8> before using them to !o$er7u! your circuit ?i.e. before turning the su!!ly 8>@. magine if the su!!ly is already connected to your circuit and you suddenly turned it on not no$ing that the !revious setting might be as high as "0-^ :ill the e=!erience from $hat is going to ha!!en be $orth it] &ortunately our laboratories are no$ eui!!ed $ith more advanced eui!ment. %ho$n in &igure is a !rogrammable DC !o$er su!!ly. t is similar to the one in &igure 5 but the settings and controls are no$ digital ?ey$ord !rogrammable@. 4sage of this eui!ment is not dicult once the o!eration of !reviously discussed !o$er su!!lies are $ell understood. +ne evident advantage of this one is the circuit does not need to be disconnected !hysically to OisolateQ from the su!!ly. *n 8>8$$ button is available to s$itch these su!!lies. DC su!!ly _1 is +G as sho$n in &igure .
F!"ure . Pro"ra**abe 1C Po'er /uppy (r!pe 2utput%
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)#&#) $unctionSignal 7enerator he function or signal generator ?sim!ly called as s!"-"en@ is an eui!ment that is basically an *C signal source. he DC !o$er su!!ly is also a signal source but gives only DC voltage.
,- D>C Connector $emale F!"ure 3. /!"-"en set at &.000&56 and &0,pea-to-pea (,pp% eve.
%tudents from their !hysics courses should already be familiar $ith $aveform conce!ts such as am!litude freuency !eriod as $ell as the diJerences bet$een a sinusoidal suare and triangular $aveforms. %ho$n in &igure / as an e=am!le is the sig7gen set at 1.0001IF $ith 10-!ea7to7!ea ?-!!@ level. Gote that although it dis!lays 10-!! the sig7 gen might not necessarily be able to su!!ly the e=act 10-!! ?e.g. it might be attenuated to say )-!!@. f that is the case ho$ do $e determine if $e are using a true 10-!!] +ne $ay to test is to use the oscillosco!e and ASSUME that as a measuring tool it is $ell7calibrated ?see %ection 2.1.5 Eui!ment Calibration@ and $oring !ro!erly. he same case might hold for freuency setting but for most basic circuits accuracy deviation of about 100IF is tolerable ?e.g. 0.00IF or 1.100IF can most liely re!resent the true 1.000IF@.
,- D>C Connector Male
F!"ure +. /!"-"en probe. he c!rcu!t-end are red and bac a!"ator c!ps 'h!e the s!"-"en end !s a BNC connector.
he only !ro!er !robe that must be used for sig7gen is the one sho$n in &igure ). Gotice that one end uses red and blac2 alligator cli!s ?used for the positive and negative res!ectively@. #ro!er !olarity should al$ays be observed. he cli!s are to be connected to the circuit ?similar to the usage $hen dealing $ith DC !o$er su!!ly@. n other $ords the color7coding is >8" a suggestion. *t the other end the connector is a *ae 50` 9GC connector. he #e*ae 50` 9GC !ort is sho$n in &igure /. 9GC is used for a secured'loced match and is not a straight7for$ard !lug7and7!lay connector. he laboratory instructor must demonstrate the !ro!er *at!n" and un-*at!n" of this ty!e of connector. +f course these are technical terms.
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)# Analog 8scilloscope +scillosco!e is a basic measuring tool used to dis!lay am!litude variation of a signal over time. he functionalities and e=tended ca!abilities of digital oscillosco!es can be easily understood $ith the understanding of the analog ones. *nalog oscillosco!es are basically buly com!ared to digital ones mainly due to the cathode7ray tube used for dis!lay ?green !hos!hor grid sho$n in &igure @.
F!"ure 7. Anao" osc!oscope se#-ca!brat!on us!n" bu!t-!n ,pp &56 s8uare-'ave s!"na.
*n e=am!le of oscillosco!e !robe is sho$n in &igure 10. +ne end is also a male 9GC connector ty!e $hile the other end is !I$$E0E>" $ith that used for sig7gen. n order to dis!lay a stable signal it should be referenced'grounded !ro!erly ?i.e. signal is not Xoating@. he !robe !in is suitable for inserting to a !rotoboard'breadboard. he !robe ca! $ith hoo is an accessory that can be used for clam!ing'!robing on one leg ?lead $ire@ of a circuit com!onent say of a resistor. hese same !robes can be used for digital oscillosco!es.
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Probe Cap ;ith oo2
Probe Pin Fe%posed ;hen Probe Cap is removedG
7round or reference F=negativeHG clamped ;ith an alligator clip
D>C connector
Probe Compensation Fattenuation setting slide s;itchG
F!"ure &0. 2sc!oscope probes.
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)# !igital 8scilloscope Digital oscillosco!es are more 9user-#r!endy: than analog ones ?C*4+G> no eui!ment is designed as fool7!roof@. %ince it is digital e=tended functionalities such as storage acuisition Bltering etc. are easily em!loyed. *s mentioned in the !revious section $oring $ith this one ?see &igure 11@ is relatively intuitive once the o!eration of analog oscillosco!es are observed. Io$ever our laboratories no$ are eui!!ed $ith digital ones even for introductory courses such as EEE ",. hus a dedicated e=!eriment $as designed to e=!lore the functionalities of this digital oscillosco!e. n any case if a relatively ne$ eui!ment comes available $hatever it may be it is a good !ractice to read the user manual guide Brst. Gon7 engineering individuals usually tae their ne$ eui!ment out of the bo= to use it right a$ay. hey often disregard the user manual enclosed $ith it ?e.g. got a ne$ mobile !hone]@. n doing so they $ill not be able to e=!lore the full ca!abilities of their eui!ment and $orse to troubleshoot even $hen basic !roblems arise.
F!"ure &&. 1!"!ta 2sc!oscope
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)#&#, E*uipment Calibration 4n7!acing ne$ eui!ment assumes that it functions as e=!ected. &or e=am!le a !o$er su!!ly set to generate 5.0-dc ?as dis!layed'read@ must read an e=act 5.0-dc $hen measured by a voltmeter ?as also dis!layed'read@ ust as $e e=!ect it to be. n fact there are four !ossible scenario for inter!reting the values dis!layed. Let us stic $ith the e=am!le given above these are> i. #o$er su!!ly is correct voltmeter is correct ii. #o$er su!!ly is $rong voltmeter is correct iii. #o$er su!!ly is correct voltmeter is $rong iv. #o$er su!!ly is $rong voltmeter is $rong n fact there is a Bfth case and it is too $ides!read that it is $orth mentioning here. v. he inter!reter'student is $rong all along Io$ do $e determine $hich one is the true =correctH] his is $here calibration comes in. Eui!ment must undergo !eriodic evaluation to determine if they are still functioning the $ay they are e=!ected to be. he mechanisms inside these eui!ment degrade $ith time ?e.g. magnets inside a multimeter@ and $ith freuent use. hus re-tun!n" is necessary ust lie ho$ a musician retunes a guitar. his is $hat $e call calibration and is only !erformed by silled electronics technicians. Io$ $ill this aJect our $or or e=!eriment] :hat if $e do not no$ if the eui!ment $e are using are $ell7calibrated] +r it is already many years after the eui!ment $as last calibrated] &or the sae of !erforming instructional e=!eriments it is safe to assume that the measuring tool/equipment is the one that is ;ell5calibrated ?lie scenario ;ii< above but ho!efully $e have ;i<@. Doing research e=!eriments ho$ever reuires all tools and eui!ment to be $ell7 calibrated. (oing bac to our e=am!le even if the !o$er su!!ly dis!lays 5.0-dc but say the voltmeter reads a diJerent one then $e $ill ASSUME that the voltmeter as the measuring tool reading is the true vaue A then adusting the !o$er su!!ly might be necessary to achieve a s!eciBc target value.
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)#) Laboratory Components Laboratory com!onents are the com!onents $e see in our schematic'circuit diagrams. Iere $e $ill discuss t$o basic ty!es of electronic com!onents> ?a@ passive and ?b@ active com!onents. he former being pass!ve; dissi!ates energy and hence introduce losses. hese com!onents do not reuire a source of energy to !erform their intended o!eration. +n the other hand active com!onents reuire a source of energy. 3ost active com!onents are non7linear and can am!lify a signal. &or e=am!le if the in!ut is 5- then it is !ossible for the out!ut to reach a voltage greater than the 5- in!ut ?a form of am!liBcation@.
)#)#& Passive Components his section $ill familiariFe the students on the basic com!onents used in EEE instructional laboratories. t is e=!ected that students already no$ the !rinci!les behind their o!eration and the underlying circuit analysis ?EEE "1'""@.
)#)#&#& 0esistors Resistors are the most fundamental and commonly used of all the electronic com!onents. Resistors basically resist or regulate the Xo$ of current running through the circuit.
here are several ty!es of resistor based on com!osition material tolerance accuracy and $attage. Each is suitable for a s!eciBc a!!lication. &or e=am!le high $attage resistors are used in !o$er electronics $hile Blm resistors ?no$n for lo$7 noise characteristic@ are used for radio communication electronics. &or instructional !ur!oses $e are only interested $ith the resistance value and hence a ty!ical ,7band resistor ?can handle u! to 0.25 :atts@ is sucient ?see &igure 12@.
F!"ure &.
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Resistor Value Reading Determining the value of a resistor $ith four ?,@ color bands is straightfor$ard. *lthough the color7coding is intuitive ?i.e. visible s!ectrum@ the student is encouraged to develo! their o$n mnemonics to hel! them identify the resistance more easily. &or e=am!le blac suggests darness or absence of something so it re!resents Fero ?0@. his hel!s rather than using 9797R7+7 [7(797 -7(7: ?(7%7Gone@. &urthermore the said mnemonics has " 9s S " (s $hich might result to confusion. he additional bands on 57 and 7band resistors !rovide better tolerance accuracy and additional information about tem!erature coecient. hese are high7grade resistors and are too *uch to be used for instructional !ur!oses. &or resistor $ith , color7bands> 1 band 1st digit 2nd band 2nd digit 3ulti!lie "rd band r th oleranc , band e ?(old75U %ilver710U and Gone720U@ st
&or e=am!le if $e have [ello$7-iolet7 Red7(old then $e have , 10 5U
or basically ,./`. Io$ can $e be so sure that $e are reading the color band in the correct seuence and not the other $ay around] :ell did $e ust mention that the ,th band can only tae on gold silver or none] Euivalently the Brst band cannot tae on these colors.
F!"ure &).
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Potentiometer $o $ire7lead resistors have B=ed resistance value but often times $e need a s!eciBc and'or out7of7B=ed7standard resistance value in our circuit design and im!lementation. his maes variable resistor or !otentiometer ?dubbed as pot @ a useful tool. #otentiometer is a three7terminal com!onent $ith variable or adustable resistance. t can be thought of as t$o resistors in series that simultaneously change values $ith movement of the $i!er ?see &igure 1,@.
F!"ure &4. Potent!o*eter? actua (e#t%; eectr!ca *ode (*!dde% and usua eectr!ca sy*bos (r!"ht%. =>
* !otentiometer is identiBed $ith its value ?usually !rinted on its casing@. %u!!ose that $e have a 10` !otentiometer. 4sing an ohmmeter the 10` or a close value can be measured on end7to7end ?in the diagram it is "71 or 17" since resistors are !assive com!onents and do not have !olarity@. :e can get the variable resistance by ta!!ing the terminal 2 and using either terminal 1 or " for the other end. *dusting the $i!er ?corres!onds to terminal 2@ changes the resistances of 172 and 27" OresistorsQ simultaneously. o assess our understanding su!!ose again that $e have a 10` !otentiometer and 172 measures ,` then the e=!ected value to be measured on 27" $ould be] CAU"I8> > *dusting the $i!er on e=treme !ositions ?i.e. 0 1 see &igure 1,@ can result in a technical short on either leg $hich $ill dra$ overload current from the !o$er su!!ly if the circuit is not !ro!erly designed.
%hort circuit events can cause fire. hus as a good !ractice a 100` resistor or near7value is usually !lace in series $ith a !otentiometer. n the event that an unintentional short $as set in !otentiometer the 100` $ill still be able to regulate the Xo$ing current. Io$ever diagrams in our e=!eriments do not include this 9sa#ety: resistor. his is for student to evaluate mistaes on their o$n. he smell of a burnt !otentiometer is not an inviting e=!erience nor memory. *lso it is for students to develo! critical thining in circuit design considerations. n summary it is essential that students understand the o!eration of each tool before they can realiFe its limitations and !ossible !recautions. %ome !otentiometers available in our instructional laboratories are !acaged in a !otentiometer bo= ?combination of 100` 1` 10` 100` and 13` !ots@. Io$ever some of them might have already been damaged'burnt'shorted by !revious curious students. hus it is also a good !ractice to chec2 potentiometers individually using ohmmeter before using them. %ingular !otentiometers are also available in the laboratory. he metal casing and the $i!er nob although made u! of metallic conductors are isolated $ith the !ins. hus it is safe to adust the $i!er $hile
holding the metal casing even if the circuit is !o$ered7u!. he siFe of !ins of an actual !otentiometer may vary. he actual one sho$n in &igure 1, can be inserted in a !rotoboard. n other cases alligator cli!s can be used. Tust be a$are that adacent cli!s may get shorted since !otentiometer !ins are s!aced closely together.
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)#)#&#) Capacitors *nother essential com!onent in electronics is the ca!acitor. his device stores charges and maintains energy in its electric Beld. he % unit for ca!acitance is &arad ?in honour of 3ichael &araday for his maor contributions in the Beld of electromagnetism@ *lthough considered a !assive com!onent there are !olar and non7!olar ty!es of ca!acitors. his de!ends on the materials used as dielectric inside the ca!acitor. %ome materials !ermit only one direction for the Xo$ of dis!lacement current $hile others !ermit bi7directionality. Gon7!olars include ceramic mylar and Blm ca!acitors. Electrolytic and tantalum ca!acitors are !olariFed. 3ost blo$n7u!'burnt ?usually the Brst aJected in fault conditions@ com!onents in a circuit are ca!acitors.
F!"ure &. 1!@erent types o# capac!tors; both non-poar and poar. =3>
E=tra care should be observed before !o$ering7 u! circuit $ith !olar ca!acitors. Io$ do $e determine $hich leg is the !ositive'negative] f the com!onent is brand ne$ the longer leg should be the !ositive. n other cases ?e.g. legs are cut at same length@ marings should be available on the body of the ca!acitor. *s sho$n in &igure 15 electrolytic ca!acitor indicates negative band $hile tantalum ca!acitor sho$s the !ositive mar. Ca!acitance values are !rinted either as7is ?see electrolytic ty!e@ or by code ?see ceramic ty!e@. Let us e=amine the electrolytic ca!acitor in &igure 15. he absolute ma=imum voltage it can handle is 1-. f charged above that value then the ca!acitor $ill e=!lode. he ca!acitance is ,/00u& $hich is euivalent to ,./m&. &or the human brain it is easier or convenient to !rocess the information ,./m&. :hy do you thin that manufacturers !refer the label ,/00u& as com!ared to ,./m& given the fact that they are ust the same] :ell $hile you are thining the reason behind that logic let us share a story of buying com!onents in an electronics sho!\
EEE %tudent> ? o saes ass!stant @ O10 !ieces of ,./m& 1- electrolytic ca!acitor !lease.Q %ales *ssistant> O%orry but $e do not have ,./m&.Q EEE %tudent> ? /addened because h!s on" tr!p to the shop '! be useess. h!ns #or a *o*ent. Ased the saes ass!stant a"a!n.@ OCan have 10 !ieces of ,/00u& electrolytic ca!acitor !lease]Q %ales *ssistant> O+ay %ir. :hat voltage rating]Q EEE %tudent> ? D deep !ns!de. @ Q1-. hans^Q %ales *ssistant> O+ay. :ait for a moment.Q
1 ) Iaha^ :hat a funny story^ %tudents might encounter a similar e=!erience. *ny$ay the main reason $hy the dot maring is highly discouraged is that it might get erased easily. 3istaing ,/m& for a ,./m& can greatly aJect the circuit o!eration by design. +n another note ceramic and mylar ca!acitors usually use "7 or ,7 character code to indicate the ca!acitance value. he reading is similar $ith the resistor color bands only that the value is already !rinted here. 12 Gote ho$ever that the resulting value is not &arad but !ico7&arad ?!& or 10 @. Ca!acitance values are usually in the !ico7 nano7 micro7 and milli7 ra nge so it $ould be easier to refer to the smallest unit. *n e=am!le is sho$n in &igure 1 $ith value 10
,/000
,/
0.0,/
he last character usually denotes the tem!erature coecient and can be disregarded for instructional !ur!oses. F!"ure &. . Cera*!c capac!tor vaue read!n". =+>
)#)# Inductors Lastly $e consider inductors as an essential com!onent in electronics. his device ee!s magnetic Xu= and stores energy in its magnetic Beld. he % unit for inductance is Ienry ?in honour of Tose!h Ienry for his $or on electromagnetic induction@. :e $ill not discuss inductors in detail but sho$n in &igure 1/ are common ty!es of inductors.
F!"ure &3. 1!@erent types o# !nductors. =7>
%ome inductors loo lie resistors but in a closer vie$ inductors are more OcurvyQ. he reason is that inside it is a $ound coil of magnetic $ires as com!ared to the ty!ical resistor manufactured using carbon. ransformers ?a magnet core $ith $ires $ound around@ can serve as inductors.
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)#)#) Active Components *ctive com!onents are electronic com!onents that reuire a source of energy to o!erate. 3ost of them are non7linear and can !rovide signal am!liBcation. EEE ", is not focused on active com!onents but $e introduce them here any$ay. E=am!les of active com!onents are> 1. Diodes 2. %!ecial7!ur!ose diodes ?e.g. Light7emitting Diodes or LEDs@ ". 9i!olar Tunction ransistors ?9Ts@ ,. &ield EJect ransistors ?&Es@ 5. *nalog ntegrated Circuits ?e.g. o!erational am!liBers or o!7am!s@ . Digital ntegrated Circuits /. Detectors and emitters
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)#3 Laboratory "ools :e $ill deBne laboratory tools as !"ht-'e!"ht !ortable things that $e use in the laboratory. ncluded here are the multimeters galvanometers and !rotoboard. he in7de!th discussion on multimeter is reserved in a later section ?see %ection "., Circuit7Level *nalysis of the 3ultimeter@
)#3#& Multimeter 3ultimeter as the name im!lies measures multi!le electrical uantities including resistance voltage and current. %ome advanced multimeters can measure ca!acitance and even inductance but for basic electronics using multimeters $e $ill only deal $ith the three fundamental uantities !rovided by the +hm8s La$. he multimeter or meter shorthand can be therefore referred to de!ending on the intended function> voltmeter A if measuring voltageM ammeter A if measuring currentM ohmmeter A if measuring resistance. &rom this early !oint let us al$ays remind ourselves that in using multimeter to measure current and voltage>
3ultimeters both analog and digital easily get damaged through misuse by students $ho do not understand the t$o statements above. he $ords above are in fact already redundant. &or EEE ", it is 2GAH to mae this ind of mistae at Brst but re!eating the same mistae is G+ ustiBable A it is someho$ un$ise. he most common damage done to multimeters is a blo$n7u! fuse caused by overcurrent. %tudents forcefully connect the meter in !arallel to measure current A $hich is totally ;rong ^ f you still do not understand $hat is being discussed
here then thin of it again and again.
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)#3#&#& Analog Multimeter &or EEE ", $e $ill Brst use analog multimeters and learn about their ca!abilities and limitations in early e=!eriments. *nalog multimeters available in the laboratory are sho$n in the Bgure belo$.
F!"ure &+. Anao" *ut!*eters.
Gotice that the multimeter on the left has B=ed !robes $hile the one on the right has detachable !robes but that is not really im!ortant. hey also have the same set of selection nobs since they use the same galvanometer scale ?the calibration $ith the needle !ointer@. :e $ill discuss an in7de!th analysis of analog multimeter in the ne=t cha!ter under %ection "., Circuit7 Level *nalysis of the 3ultimeter . nuisitive readers are advised to um! to that section before !roceeding $ith ne=t sections in this cha!ter. he color coding of the !robes is intuitive A red for positive and blac2 for negative . 9asically both !robes are ust conductor $ires so they serve the same !ur!ose. hat is they can be technically interchanged. Io$ever to avoid confusion $e follo$ the color code es!ecially that $e are dealing $ith analog multimeter $here !ro!er !olarity is a must.
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Using the Multimeter to Measure Voltage, Current and Resistance Let us tae a closer loo on the selector nob ?see &igure 1@ and the calibration scale ?see &igure 20@. &igure 20 is ust similar to the 1m* movement galvanometer scale only that it indicates lot of marings. Gonetheless the o!eration is the same. o measure voltage turn the selector nob to the a!!ro!riate DC- level. &or safety al$ays choose the range $ith the nearest higher level than the e=!ected value to be measured. &or e=am!le if e=!ecting to measure )- set the meter to 10- instead of 50-. his $ill give us better accuracy in gathering data $hile !rotecting the multimeter from o!er-!oltage". he same !ractice goes $hen measuring current ?DCm*@. n reading the measured DC- or DCm* value use the calibration scale ?the line $ith marers@ ust belo$ the re#ector strip. he reXector stri! is used to avoid paraa error . he needle !ointer $ill cast a shado$ some$here along this stri!. he shado$ therefore is on the same surface !lane $ith the calibration scale. hus reading the value $ould be easier. he corres!onding reading scales ?the numbers@ to use for voltage and current readings are belo$ the reXector stri!. +bserve the range of the reading scales and the range on the selector nob. :hat do you notice] s there a !attern] [es there is. he full 7scale readings are 10 50 and 250. *ll of $hich are multi!les of the range on the selector nob. Let us e=!lain this more closely. f e=!ecting to measure )- it $ould be easier ?and safe@ to set the multimeter nob to 10- and use the 0 to 10- reading scale since the !ro!ortionality constant or factor to use is 1. he needle !ointer $ill fall on ?or near@ the column of ) ,0 and 200. 9ut of course the reading $ould be most convenient if read on the calibration scale $ith ). 4sing ,0 reuires a factor of 5 $hile using 200 reuires a factor of 25. *s a test of understanding if e=!ecting to measure for instance a voltage level of 2."- $here should $e set the selector nob] :hat reading scale is the most convenient to use] his is ust a matter of ratio and !ro!ortion.
F!"ure &7. Anao" *ut!*eter seector nob. =>
2 " 3easuring resistance using analog multimeter is a bit diJerent from measuring voltage and current. he calibration and reading scale are located above the reflector stri! A obviously $ith the ` symbol ?see &igure 20@. he e=treme ends are ` and 0` re!resenting o!en and short conditions res!ectively. he ohmmeter selector nob instead of a range is a set of multi!liers. he resistance calibration scale is >8" linear as com!ared to that of DC-'DCm*. he distances bet$een marings $ith smaller value are large and they decrease as the value tends to . :hy is that so] +f course there is an engineering reason behind it and $e $ill learn about it in future e=!eriment's. +bviously $e can get higher accuracy if the needle !ointer falls on values $ith smaller resistance number. his is $hy it is !referred to use the highest !ossible multi!lier de!ending on the e=!ected resistance value $hen measuring.
he current marings in light blue on each multi!lier ?see &igure 1@ signiBes the amount of current that is running on ohmmeter leads $hen shorted. Energy is available since ohmmeter o!erates $ith a battery. his im!lies a !recaution in using an ohmmeter. n measuring resistance the circuit or resistor under test should not be !o$ered7u!. f it is then the !o$er su!!lied to the circuit under test and the !o$er given by the ohmmeter might aJect the reading. *lso there are com!onents such as integrated circuits ?Cs@ that cannot handle current as high as 150m* ?1= setting@. Care should be observed before measuring resistance on these inds of electronic com!onents. +n the other hand the ohmmeter is also useful es!ecially in testing other electronic com!onents if $oring or not ?e.g. light7emitting diodes or LEDs A ho$]@.
0eector Strip
F!"ure 0. Anao" *ut!*eter ca!brat!on scae. =)>
f the analog multimeter is not in use turn it 8$$ by s$itching the selector nob to +&& to conserve its battery^ Digital multimeters automatically s$itch oJ $hen idle for a certain time.
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$ero-ing the Meter %cale &or ohmmeter ho$ever the default !osition of the needle falls on the left7most $ith ` re!resenting o!en circuit. 9efore maing any resistance measurement using analog multimeter it is necessary to al$ays Fero the scale. t maes sense since any reading should al$ays start $ith Fero as reference. Each multi!lier setting might have diJerent initial Fero !osition.
F!"ure &. Jero-!n" the *eter scae. =4>
o Fero the scale short the leads together and turn the 6ero adKust nob ?see &igure 1@ until the needle !ointer falls e=actly on 0` mar as sho$n in &igure 21. here might be some settings $here the scale could not be Fero7ed. Gote that human body can be thought of as a single $ire conductor. #utting hands in contact $ith the leads as sho$n in the Bgure above is Bne only $hen Fero7ing the scale. f already measuring resistance of a resistor for e=am!le then do not cli! the legs of the resistor to the ohmmeter leads using hands. he reading might be the combined resistance of the resistor and human body. 9etter !lace the resistor on the insulated table or on the !rotoboard before taing measurements. 6ero7ing the meter scale is essentially reaching the full7scale current. hat is $hy the 0` scale in &igure 20 is aligned $ith the full5scale current ?right7 most mar@ on the calibration scale.
Connecti!it&/Continuit& 'est #erforming connectivity or continuity test is essential for basic debugging'troubleshooting. n analog multimeters at ohmmeter mode a shorted connected or cont!nuous condition must dis!lay 0`. * good $ire conductor ideally has a resistance of 0`. his is most useful in checing continuity of connecting $ires alligator cli!s connectors etc. Determining $hich holes are connected and $hich are not in a !rotoboard can also be checed easily using connectivity test.
Digital and other analog multimeters have advanced indicator for connectivity test. 3ost are of the form of a buFFer. t $ill sound once the device under test is checed to be connected.
2 5 Gote that some connecting $ires or cli!s are connected if !laced in a certain !osition ?e.g. t$isted@ $hile at other orientation may a!!ear to be not connected. :ires are covered $ith !lastic insulation so visual ins!ection might not be !ossible. Tust be a$are that this scenario is not im!ossible ha!!en. 3ost students get lost if their circuit is not functioning as e=!ected A only to Bnd out that one of their connecting $ires is Oo!enQ.
)#3#&#)
!igital Multimeter
* Ouser7friendlyQ ty!e of multimeter is the digital version. Io$ever ust lie socially $e should not tae the friendliness of others for granted. hese multimeters although contains !rotective circuits still have their limits. %o the Ouser7friendlyQ term might be a misleading one for us. &or e=am!le some digital multimeters can detect over7 voltage even if the selector nob setting is unintentionally unchanged to the !ro!er setting. f set on such condition for some s!eciBc long time the internal !rotection circuitry might eventually fail thus damaging the tool. n summary !ro!er care should ALBAJS be observed in handling A>J laboratory tool or eui!ment.
F!"ure . 5and-hed d!"!ta *ut!*eters.
he digital dis!lay $ould be the most obvious distinction of a digital to that of an analog multimeter as sho$n in &igure 22. he blac2 !robe is al$ays !laced on the C8M ?common@ !ort and the red !robe on 6! !ort. +ther !orts are used for high7current a!!lications and those are not in the sco!e of this course.
:e also have bench digital multimeters as sho$n in &igure 2". his ty!e of multimeter is more robust than the hand7held version ?the siFe and $eight can e=!lain $hy@. ts !ro!er use is no !uFFle once the student is $ell7familiariFed $ith analog and digital multimeters.
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F!"ure ). Bench d!"!ta *ut!*eter.
%o if the students $ere to as $hich is better to use the analog or the digital multimeter] :hatever the ans$er may be engineers should develo! a $ay of thining on ho$ to reason out for the choices that they mae ?es!ecially $hen defending say an engineering design@. Engineers do not mae decisions right a$ay. hey Brst thin of o!tions and alternatives then they $eigh them. *fter all there should be a reason for everything.
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)#3#) !@Arsonval 7alvanometer or &mA Movement he D8*rsonval galvanometer or 1m* movement is basically a !ermanent magnet moving7coil transducer that uses the !rinci!le of electromagnetism in determining the magnitude of !assing current. he needle deXection indicates the magnitude of current. he galvanometer is calibrated $ith full7scale of 1m* A hence the name 1m* movement.
F!"ure 4. &*A *ove*ent.
here are t$o !orts to connect in order to use this 1m* movement ?see &igure 2,@. &or !ro!er !olarity the color code is here once again. 9ut $ait do currents have !olarity] +f course the ans$er is no they do not have !olarity. Rather the red and blac color code here re!resents the direction of the current. Gote that $e are using analog device and !ro!er O!olarityQ must al$ays be observed. he current must enter the positive FredG !ort and e=it the negative Fblac2G !ort. f interchanged then the needle $ill try to deXect more to the left ?i.e. on the OnegativeQ of the scale@ and this might damage the tool. %ince this tool measures current ?u! to 1m* only@ $hat should be the best $ay to chec if this measuring tool is $oring !ro!erly or not]
2 )
)#3#3 ProtoboardDreadboard ranslating circuits from diagrams on !a!er to actual im!lementation is an essential sill one needs to master in this course. he O!a!erQ that $e $ill use in laying7out our circuits is the !rotoboard ?short for !rototy!ing board@. t is sometimes called breadboard since the holes resemble that of a bread ?$oring in the laboratory can get one really hungry@. &or discussion !ur!oses let us stic using the term !rotoboard. he !rotoboard conveniently !rovides connected holes in a ro$. %ince the holes are arranged in a matri= fashion ?see &igure 25@ the uestion no$ is $hich ro$s are connected and euivalently $hich are not. Let us begin by describing a short ro$ and a on" ro$.
Long ro;
Short ro;s
Connectin g ;ires
Canal
F!"ure . Protoboard. =&0>
9asically the holes in a short ro$ are internally connected. *dacent short ro$s as $ell as short ro$s across the cana are G+ connected. he holes in a long ro$ are internally connected but de!ending on the brand the other half may or may not be connected. he e=am!le in &igure 25 sho$s a discontinuous red ?K@ and blue ? 7@ lines. his indicates that long ro$s do not continue on the entire length the !rotoboard. hat is $hy $e can see connecting $ires Num!ing8 from one long ro$ to another on the other half. Long ro$s have ?K@ and ?A@ labels since these lines are usually used as !o$er !orts ?e.g. the K and A of a 5.0- su!!ly@. 9ut $hy do $e reserve longer lines for the !o$er !orts] t is fairly sim!le. f the circuit has a lot of com!onents it $ill consume the $hole !rotoboard s!ace and most liely all com!onents $ill reuire !o$er. hus !o$er !orts can be easily accessed any$here on the !rotoboard. he !rotoboard canal serves a !ur!ose es!ecially $hen using dual in7line !acage Cs such as o!erational am!liBers ?see *!!endi= C> %ome Gotes from +!erational *m!liBer ?+!7*m!@ Datasheets or &igure 2@. ry to loo closely on &igure 2 on ho$ Cs are !laced on the !rotoboard.
Engineers do not really need to memoriFe $hich holes are connected and $hich are not. Remember that $e have the tools. :hen in doubt $e can insert connecting $ires in a !air of holes and use a multimeter to do a connectivity test.
+n a side note true engineering education $ill not teach its students by maing them memoriFe stuJ ?e.g. formulas here7and7there this7and7that etc.@. nstead it $ill teach its students by guiding them in learning ho$ to solve !roblems and overcome obstacles.
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)#3#3#& Protoboard Biring %etting7u! a circuit on a !rotoboard needs !atience es!ecially for Brst7 timers. f one does not no$ $hat a short and o!en connected and not connected mean then he'she $ill surely get sno$balled in constructing a circuit. t might tae more time and !ractice for others de!ending on the learning curve of the student. Gonetheless constructing a circuit on a !rotoboard should be an easy tas.
F!"ure . Protoboard '!r!n" o# t'o co*pe c!rcu!ts? *essy '!r!n" (e#t% and cean '!r!n" (r!"ht%. =&0>
Let us com!are the $iring of t$o com!le= circuits sho$n in &igure 2. 9oth use a bunch of com!onents but the $iring on the left is a bit messy com!ared to the one on the right. 9oth are $oring as intended so functionality $ill not be an issue. his scenario is someho$ similar to $riting com!uter !rograms. *s long as the code is $oring students tend not to care because it is already $oring. Io$ever $hat $ill be the !ossible disadvantage of the circuit $iring on the left com!ared to the one on the right ? I>"> his also a!!lies to com!uter !rogramming@] +bviously the one on the left is !rone to errors. Conseuently $henever there is error it $ill be hard to trace $here the error arises. his leads us to our ne=t section A $hich is one of the most important s(ills every EEE student must !ossess.
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)#3#3#) !ebugging"roubleshooting Circuits
'&&(
*fter constructing a com!licated circuit it is not uncommon for it to be non7functional. his may be due to $iring'connection errors faulty !arts and'or incorrect eui!ment settings ?e.g. $rong !o$er su!!ly setting@. he !rocess of Bnding and correcting these !roblems is called debugging. t is very easy to get lost in the myriad of !ossible sources of error. *lso thining of !ossible solutions for an unno$n !roblem is an over$helming tas. Debugging circuits ?ust lie debugging !rograms@ might be a highly frustrating tas for EEE students es!ecially if one does not no$ the causes of such un$anted errors. Io$ever even if the nature of the !roblem is not identiBed beforehand ?e=istence does not necessarily im!ly its nature@ debugging circuit $ould be easy if a!!roached in a systematic manner. magine if a student $ill debug a circuit that loos lie the one !resented in &igure 2?left@. Ie'she might save more time if he'she $ill ust reconstruct the entire circuit instead of Bnding $here the error is. hus it is advisable to !ractice neat $iring at the very Brst time. Debugging is a sill that reuires continuous !ractice and e=!erience. +ne must fully understand the o!eration of his'her circuit as a $hole and !er7 com!onent ?or sub7circuit@ basis before he'she can identify the !ossible causes of error. +ne cannot solve something that he'she does not acno$ledge as a !roblem in the Brst !lace. f the circuit is not functioning the $ay it is designed to then there must be !roblem's. Iere are some ti!s on debugging'troubleshooting circuits>
3ae sure that the tool used for debugging is $oring !ro!erly. &or e=am!le test Brst a voltmeter on a battery or DC !o$er su!!ly.
3ae sure that the tools are on their !ro!er setting. he circuit might be $oring !ro!erly but the measuring tool is not set correctly giving you OincorrectQ information. 9efore checing the res!onse of your circuit have the intuition to com!are it $ith the theoretical res!onse ?e.g. O I epect to *easure ., here @ . #ractical results most of the time are close to the theoretical ones. his is one !ro!er $ay to validate results. *l$ays try to as yourself M1o the data that I have *ae sense Learn the functions of various !arts of the circuit. Zno$ing them can hel! you devise tests to determine $hether or not each !art is functioning !ro!erly. est all connections. 3ost !roblems come from faulty $ires alligator cli!s !robes and even shorted com!onents.
Chec the actual $iring against the circuit schematic. * sim!le method is verifying $hich nodes are connected and $hich are not. Double chec your $iring. %tudents tend to insert $ires on unintended adacent holes on the !rotoboard. Double chec if you are using the correct com!onent values ?e.g. 1` $as used instead of 10`@.
3ae sure that all !arts and com!onents are $oring !ro!erly ?e.g. might be using a broen !otentiometer@. f you thin you have !in!ointed a !ossible source of !roblem then devise a uic and easy e=!eriment to test your hy!othesis ?e.g. connectivity test for a sus!ected faulty $ire@. 3ae sure that the !o$er su!!ly is +G and has the correct setting. Debug by follo$ing the signal !ath ?e.g. from in!ut to out!ut@. %tart checing from the su!!ly do$n to the out!ut com!onent in the circuit ?e.g. voltage measurements@.
f the circuit can be divided into stages or modules then chec them se!arately. solation is a good a!!roach in tracing the source of error. *l$ays remember that very sim!le errors are also very common errors.
"1 Engineering is the art of solving !roblems. n debugging circuits $e $ant to Bnd and correct errors. :e develo! algorithms and methods to achieve !ro!er debugging. Io$ever there is no B=ed $ay of using these debugging techniues. :e Bgure them out through e=!eriments. Debugging circuit reuires sills and e=!erience and as an art it also reuires creativity.
F!"ure 3. P51 Co*!cs? 1ebu""!n". =&>
Revisit this section until the student develo!s the sill of debugging by him'herself. n case of ho!elessness as the hel! of the laboratory instructor. he instructor $ill !robably thro$ the uestion ased by students bac to them. #resent to the instructor ho$ the tried solutions did not $or.
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3 Electrical Measurements #erforming e=!eriments is essential but gathering data and analysing S inter!reting them are more valuable. his cha!ter brieXy introduces basic conce!ts of measurement A error S linearity and accuracy S !recision. n order to recogniFe or deBne error $e must Brst dra$ the diJerence bet$een theory and !ractice. o !ut some sense on em!irical results to be obtained from the e=!eriments the students should have a good understanding of the ideal and !ractical conditions of !o$er su!!lies the characteristic of a 1m* movement and Bnally the diJerences bet$een the modes of an analog multimeter using the galvanometer scale.
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3#&"heory and Practice EEE"1 and EEE "" teach us the fundamentals of circuit theory. :hat $e $rite and solve in !a!er there assumes ideal conditions both for the eui!ment and com!onents used. &or e=am!le a 1 resistor in !a!er has no tolerance and hence the value $ill stay as 1 and a 5.0-dc su!!ly $ill stay as 5.0-dc no more no less. :e refer to these values as theoretical !alues . n !ractice ho$ever this is usually not the case. Let us tae a sim!le circuit as an e=am!le ?see &igure 2)@. &or sim!licity and as an e=am!le $e $ill only e=amine the diJerence bet$een an ideal and !ractical voltmeter. hus values of R1 R2 and the 5-dc stay as they are.
F!"ure +. (a% /!*pe res!st!ve c!rcu!t; (b% !dea vot*eter; and (c% pract!ca vot*eter
%u!!ose $e are going to measure the voltage out!ut -out of the sim!le resistive circuit at R2. 4sing the ideal voltmeter ?see &igure 2)b@ by voltage division $e should be able to measure 2.5-dc A theoret!ca vaue. Io$ever !ractical voltmeters have some internal resistance in !arallel $ith them. he !arallel resistance is usually high but for e=aggeration $e $ill assume a value of 1 ?see &igure 2)c@. 4sing the !ractical voltmeter $e can measure about 1./-dc at the out!ut. he deviation comes from the un$anted internal resistance of the !ractical voltmeter. he measured !alue is far ?or near]@ from the theoret!ca vaue. f $e are not a$are that a !ractical voltmeter has this internal resistance then $e can inter!ret the measured value as erroneous. %o ho$ do $e develo! the right intuition to determine if our measurements mae sense or not] his is $here $e should bridge theory and !ractice. *n inuisitive and clever student $ill not settle on reading measurements A he'she $ill mae sense out of it. hat is he'she can defend $hy such results $ere gathered. he error or deviation in measured value de!ends on ho$ our !ractical a!!roach deviates from ideal case. n our e=am!le if the internal resistance a!!roaches inBnity ?ideal@ then the measured value should also a!!roach a value of 2.5-dc ?ideal@.
(etting 9h!"h: deviation value in $hat $e measure in !ractice does not mean that the theories are $rong. n fact the measurements $e mae should be guided by the !rinci!les set by circuit theory.
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3#) Error and Linearity 3#)#& Error Let us begin by diJerentiating theoret!ca vaue ?-@ $ith the *easured vaue ?3-@. heoretical value is sim!ly the ideal nominal or target value $hile measured value is the actual value !ertaining to real7$orld measurement. hus error ?e@ can be deBned as the diJerence bet$een the measured value and theoretical value.
Error value is al$ays !ositive so $e tae the absolute value of the diJerence. &urther for a s!eciBc measurement the theoretical value is constant. Evaluating error in terms of !ercentage by referencing to the theoretical value is more meaningful. hus $e have U
U
3#)#) Linearity &or no$ let us not consider time variation on our data. his sim!liBes our analysis into one dimension only. Consider a system that has in!ut and out!ut. Let us tae a head!hone am!liBer for e=am!le $here the electrical signals ?in!ut@ are converted and am!liBed to !roduce sound ?out!ut@. here $ill be a certain range on the am!litude of electrical signals $here the head!hone am!liBer can convert in a !ro!ortional manner. Io$ever as the in!ut electrical signal increases further the head!hone am!liBer may saturate and !roduce an almost constant high sound level. his scenario is de!icted in &igure 2.
F!"ure 7. Input-output reat!onsh!p sho'!n" !near!ty.
" 5 he linear region of a system assuming voltages as in!ut and out!ut uantities can be described by
$here is the !ro!ortionality constant. n this region an increase in the in!ut $ill !roduce an increase ?or a decrease in some systems@ $ith a certain !ro!ortionality factor. *t the non7linear region ho$ever the relationshi! bet$een the in!ut and out!ut can be described by higher order euation such as $here
1 2
\
K
KK
are the $eights !er degree of in!ut.
he in!ut can be thought of as the inde!endent variable $hile the out!ut as the de!endent variable. %tudents are encouraged to thin of other e=am!les of system that e=hibit linear and nonlinear in!ut7out!ut relationshi!.
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3#3 Accuracy and Precision Com!ared to the e=!ected or theoretical value ho$ do $e determine the closeness of gathered actual data] Can $e call it accurate !recise or both] *ccuracy and !recision are t$o diJerent things and one must observe care $hen using either of these terms. o understand these basic conce!ts let us e=amine &igure "0.
F!"ure )0. 1!@erence bet'een accuracy and prec!s!on. =&)>
&our ?,@ target boards $ith diJerent levels of accuracy and !recision are sho$n. Let the bullseye be the e=!ected or theoretical value and the trial shots as the gathered data. he =7a=is is increasing $ith accuracy $hile the y7a=is $ith !recision. Clearly higher accuracy means that the gathered data no matter ho$ s!arse the data is have minimal error. hat is data are close to the theoretical value. +n the other hand !recision suggests ho$ gathered data are close to each other ?i.e. consistency@ regardless of the amount of error. he best condition is undoubtedly &igure "0d. Io$ever it is im!ortant to recogniFe that analysis is done after gathering the data. #erforming an e=!eriment is not targeting the theoretical data. %ome OresearchersQ tend to bias the !rocess of ?i.e. before or during the e=!eriment@ gathering data ust to conclude that they got an accurate and !recise data. his is not a good research !ractice. +ne must re!ort $hat are actually collected. *fter all there are no correct nor incorrect data A only im!ro!er e=ecution of e=!eriments.
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3#4 Circuit5Level Analysis of the Multimeter he !hysical a!!earance and overvie$ of the o!eration of multimeter $as discussed in the !revious cha!ter. 9efore $e !roceed let us again remind ourselves on ho$ to measure current and voltage using multimeters.
n this cha!ter $e $ill dig dee!er on ho$ multimeters $or in a circuit7 level !oint of vie$ A the ammeter voltmeter and ohmmeter. 9efore that $e should be able to understand voltage source current source and the characteristic of the 1m* movement. he galvanometer scale is the !rimary com!onent used to indicate current voltage and resistance in an analog sense.
3#4#& Practical Po;er Supply he !o$er su!!ly is the source and hence the circuit to be connected ?called sin( @ $ill dra$ energy from it. he redundancy of terms used here $ill hel! us understand and remember the conce!ts and later on to develo! intuition. n circuit theory ?EEE "1'""@ $e al$ays assume that voltage and current sources are ideal. Io$ever in a real7$orld scenario ?e.g. EEE ",@ some non7ideal conditions e=ist.
F!"ure )&. Pract!ca vota"e source (e#t% and pract!ca current source (r!"ht%. =&4>
* !ractical voltage source is re!resented $ith a series resistance $hile a !ractical current source has a !arallel resistance as sho$n in &igure "1. Io$ do these resistances mae the sources non7ideal] f $e connect a resistive net$or'circuit at nodes a and b of the voltage source $ith e 6olts+ the circuit $ill dra$ energy or current i . here $ill be a voltage dro! across the series resistance r . hus instead of su!!lying the full voltage e to the circuit a lo$er
level of )e * ir+ 6olts is su!!lied. he reason $hy a !arallel resistance on a current source maes it a !ractical one is left for the students to analyFe.
" ) Go$adays !o$er su!!lies are designed such that these non7idealities are if not eliminated minimiFed. :e can assume that the !o$er su!!lies in the laboratory are close to ideal ones. his section only o!ens to us that such !racticality e=ists.
3#4#) Characteristic of the &mA movement 7alvanometer Scale :e have seen ho$ the 1m* movement loos lie. nside it are !ermanent magnet coils the needle !ointer and the calibration scale for the reading as sho$n in &igure "2. he electrical symbol used is a circle $ith a letter ?A@ ?signifying *m!ere@ since it senses current.
F!"ure ). &*A *ove*ent !ns!de structure (e#t% and !ts eectr!ca sy*bo (r!"ht%. =&>
he 1m* movement is characteriFed by its internal resistance ?meter resistance@ and the full7scale current it can measure safely . n this case the full7 scale current is obviously 1m*. he internal resistance varies from one galvanometer to another. y!ical value ranges from 50` to "00`.
Gote that the follo$ing discussions $ill use the galvanometer scale to measure not only current but also voltage and resistance. s that really !ossible] 4sing circuit analysis the ans$er is deBnitely a yes. :e $ill limit our discussion on DC analysis. *C analysis $ill be tacled in later e=!eriments $here digital multimeters $ill be used.
"
3#4#3 !C Ammeter 4sing the 1m* movement to measure DC current is !retty straightfor$ard. :e only need to insert the 1m* movement to the line $here $e $ant to determine the current. %u!!ose $e have a resistive circuit $here $e $ant to measure the current ?call it c!rcu!t under test @. n this cha!ter $e denote the circuit under test in red $hile the circuit under discussion in blac for uniformity in circuit diagrams. &or sim!ler analysis $e re!resent the circuit under test by its hevenin euivalent $ith a voltage source and series resistance as sho$n in &igure "". Godes a and b are initially connected.
F!"ure )). Oeasur!n" current us!n" the "avano*eter as the a**eter.
Ge=t $e $ant to identify the current Xo$ing through the circuit # 9rea the circuit to s!lit a and b and insert the 1m* movement as suggested in &igure "". 'he 1m* movement is no$ !art of the circuit and it is then re7closed. he current $ill no$ Xo$ through the meter and the needle $ill deXect to dis!lay a reading. his scheme is fairly sim!le. Io$ever let us remember the !hysical limitations of the 1m* movement. &irst is that the 1m* movement has a Bnite internal resistance # +ne should be able to recogniFe that the reading $ill be aJected since there is an additional series resistance to the $hile the current $ith meter circuit. he current $ithout the meter is sim!ly inserted # Let us deBne ammeter as the ratio of t$o is accuracy values
K
K
Clearly if then the accuracy $ould be unity ?or 100U@. de!ends on the circuit under test and thus our ammeter should $or $ith any circuit8s euivalent hevenin
resistance value. &or an ideal ammeter $hat should be the value of ] :hat is the $orst case scenario relating and ] Lastly is it !ossible to achieve W 1] (iven the uantiBed ammeter accuracy the amount of error $ill be ?
@
, 0 he term insertion error is used since $e get this error by literally inserting the ammeter to the circuit. he im!ortance of giving a s!eciBc name $ill be evident as $e discussed the error for the voltmeter case. he second and last limitation of the 1m* movement is its full7scale limit. is constant and the ammeter can only measure values less than or eual to this value. s there a $ay to e=tend the measurement range] &or e=am!le if the needle deXects to full7scale 1m* !osition the e=tended7ammeter actually OmeasuresQ a higher value of say 10m*] his is !ossible through current division. %ince the 1m* movement can only handle u! to 1m* the remaining m* current ?real measured current is 10m*@ should Xo$ some$here else. Let the target current ?i.e. e=tended range@ be . o e=tend the range of the ammeter $e need a lo$er resistance value com!ared to that is connected in !arallel $ith the 1m* movement. his is a shunt ?another term for N!arallel8@ resistor $here the maority of the current $ill Xo$ ?see &igure ",@. Remember that current tends to Xo$ in a !ath $ith least resistance.
F!"ure )4. Etend!n" the ran"e o# the a**eter.
&igure ", sho$s ho$ to e=tend the range of the 1m* movement. %im!ly connect a shunt resistor across the 1m* movement. he uestion no$ is ho$ do $e determine the value of to e=tend from to ] :e must no$ the value of Brst. hen by ZCL $e have
:ith ma=imum current
K
+ the voltage across the nodes is
hus the value of should be
?
%ince
V then indeed ?
@
V #
@
, 1
3#4#4 !C 6oltmeter n the !revious section $e have seen ho$ sim!le it is to use the 1m* movement to act as an ammeter. n this section $e $ill use the 1m* movement to measure voltage instead. 9y +hm8s La$ # %ince the 1m* movement measures current $e only need a resistor in series to mae it act as a voltmeter as sho$n in &igure "5.
F!"ure ). 1C ,ot*eter structure us!n" &*A *ove*ent.
Let us deBne in!ut resistance of the voltmeter as ? K @# his is the resistance looing into the voltmeter. and are the measured current and voltage res!ectively of this constructed voltmeter. &or clarity the 1m* movement dis!lays current reading. :e are taing advantage of the fact that $e have the no$ledge of to indicate a voltage reading as !rovided by +hm8s La$. nstead of a full7 scale current + the #u-scae vota"e that our constructed
voltmeter can measure is
? K
@
#
Ge=t $e deBne the voltmeter accuracy. %u!!ose again that $e have a resistive circuit but this time $e use a Gorton euivalent instead ?see &igure "@.
F!"ure ). Oeasur!n" vota"e us!n" the "avano*eter '!th a ser!es res!stor as the vot*eter.
:ithout the voltmeter the voltage is voltmeter in !arallel the voltage is accuracy is ;
?
@<
# Connecting the # t can be sho$n that the voltmeter
K
K
, 2 *gain if then the accuracy $ould be unity ?or 100U@. de!ends on the circuit under test and thus our voltmeter should $or $ith any circuit8s euivalent Gorton
resistance value. &or an ideal voltmeter $hat should be the value of ] +ne might thin an outright ans$er of inBnity. f is also very large or of about inBnite value then $e have
j
?] @
K
K
he above euation does not mae sense in the very Brst !lace. 3ath tells us that this case is Nindeterminate8. o achieve ma=imum accuracy ideally $e $ant k such that
K
%imilar to the DC ammeter is it !ossible to have W 1] (iven the uantiBed voltmeter accuracy the amount of error $ill be ?
@
&or voltmeter the error is termed as loading error due to the Nloading eJect8 caused by connecting the meter $ith Bnite resistance to a circuit. deally all current in &igure " should stay $ithin the circuit under test even if $e connect the voltmeter in !arallel. his $as not the case since $e have read a current reading # translating to our voltage reading *ccuracy and error values re!resented above are dimensionless. -alues in !ercentage are !referred ho$ever $hen re!orting data. here should be no confusion bet$een the ideal conditions of voltage source and voltmeter as $ell as bet$een current source and the ammeter. &or each combination the former is a source and the latter can be thought of as a sin( .
, "
3#4#, 8hmmeter +hmmeter is the mode of multimeter that measures resistance. :e have learned that both the ammeter and voltmeter dra$ current from the circuit under test in order to get a reading. &or an ohmmeter the case is diJerent. n fact ohmmeters have their o$n voltage su!!ly. n actual this voltage su!!ly is of the form of a battery. he voltage being su!!lied by a battery is not constant over time. :ill this aJect the resistance reading] Io$ to correct or re7calibrate the ohmmeter for such changes] *nalog ohmmeters al$ays have the 6ero adKust nob. t is basically a !otentiometer used to OFeroQ the ohmmeter ?see &igure "/@. he reader is encouraged to loo bac at the !hysical structure of the analog multimeter in the !revious cha!ter. his $ill hel! in interconnecting the conce!ts discussed in this section. he ohmmeter circuitry constructed using the 1m* movement is sho$n in the Bgure belo$.
a
b F!"ure )3. 2h**eter structure us!n" &*A *ove*ent.
Let us deBne the resistance seen looing into the ohmmeter structure as ? K
@
%horting the leads a and b $e can NFero8 the ohmmeter such that
%u!!ose that $e are to measure a resistor $ith unno$n value as sho$n in &igure "). :e connect the ohmmeter leads to the legs of the resistor. he measured or dis!layed current $ill no$ be
?
K
@
, ,
F!"ure )+. Oeasur!n" the res!stance o# an unno'n res!stor us!n" anao" oh**eter.
Iere $e deBne a !arameter called meter deection denoted by . his is a measure of ho$ the needle deXects in reference to the full7scale !osition. hus ; <. t can be easily sho$n that
K
he 1m* movement dis!lays the !osition of the needle hence the value # f $e of no$ the value of + then $e can determine the resistance value of the unno$n resistor using the euation above.
, 5
4 E%periments he conce!ts !resented in the !revious cha!ters serve as a strong foundation in !erforming the reuired e=!eriments as $ell as develo!ing critical analysis on the data to be gathered. his cha!ter contains the inventory of reuired e=!eriments for EEE ",. * !re7lab sheet is available for students to ans$er and submit in class before each actual e=!eriment either in7!rint or hand$ritten on a !ad !a!er. he in7lab sheets ho$ever are not to be submitted. hese serve as guide for students throughout each e=!eriment. *fter gathering data and analysing them some reuired discussion uestions are to be ans$ered. he com!lete concise and coherent documentation in EEE format should be submitted !er grou! A t$o ?2@ $ees after the e=!eriment is Bnished. Gote that some e=!eriments *!"ht tae u! t$o ?2@ meetings de!ending on available schedule. *ll e=!eriments for EEE ", should be !erformed throughout the semester.
he e=!eriments !resented here are in chronological order but the delivery still de!ends on the laboratory instructor. * SA$E"J KUI must be !assed by a student before he'she !roceeds $ith any e=!eriment. f the student fails the uiF then he'she $ill be mared absent for the e=!eriment scheduled for that day. n other $ords he'she can only !erform an e=!eriment unt! he'she !assed the safety uiF. he format and administration of the uiF again de!end on the laboratory instructor.
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Electrical Measurements Laboratory EEE 34 Game> YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY %tudent Gumber> YYYYYYYYYYYYYYYYYYYYYYYYYY %ection> YYYYYYYYYYYYYYYYYYYYYYYYYY Date> YYYYYYYYYYYYYYYYYYYYYYYYYY E%periment -a FPre5LabG Dasic Measurements
#ut a chec on the bo= if the corres!onding tas is accom!lished. *. Toin the class section8s online grou!. &ound in EEE ", %tudent Laboratory 3anual\ 9. Read and understand Class #olicies; Cha!ter 1 %afety #ractices in the Laboratory ;1< %ection 1.1 Care in handling and use of a multimeter and %ection 1.2 Laboratory Rules and Regulations A $ith all their sub7section's if a!!licable. C. Read and understand %ection 2.".1 3ultimeter %ection 2.1.1 #o$er %u!!ly %ection 2.2.1.1 Resistors %ection 2."." #rotoboard'9readboard %ection ".1 heory and #ractice and %ection ".2.1 Error A $ith all their sub7section's if a!!licable. Do'ans$er the follo$ing ?indicate all references used@> 1. List the advantages'disadvantages of using analog meters over digital meters. :hich is better to use and $hy]
2. Dra$ t$o se!arate diagrams sho$ing a multimeter measuring ?a@ voltage across and ?b@ current through a resistor in a sim!le one7loo! circuit.
". ?h!s !te* !s N2 re8u!red.@ :hat are the diJerent ty!es of resistors ca!acitors and inductors] :hy these com!onents are manufactured using diJerent ty!es of material]
0E$E0E>CE S<
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Electrical Measurements Laboratory EEE 34 (rou! Gumber'Letter> YYYYYYY 3embers> YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY Date> YYYYYYYYYYYYYYYYYY YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY %ection> YYYYYYYYYYYYYYYYYY YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY
E%periment -< Dasic Measurements I#
8DEC"I6ES a@ Learn to use the !o$er su!!ly !rotoboard and analog multimeter. b@ Learn to measure voltage current and resistance in sim!le circuits.
II#
MA"E0IALS N EKUIPME>" ?"@ diJerent value resistors ?diJerent $ith other resistors belo$M for #art *@ ?1@ 1` resistor ?1@ 100` resistor ?1@ 5.1` resistor ?1@ 50` resistor ?1@ digital multimeter ?D33@ ?1@ single !o$er su!!ly !rotoboard connectors and ?1@ analog multimeter ?*33@ cli!s
III# P08CE!U0E >8"E< Jou can use a digital multimeter F!MMG to counter5chec2 your measurements using analog multimeter FAMMG# A# Measuring 0esistance using 8hmmeter 1. $eroing the meter scale# Choose a resistance range. %hort the t$o meter leads by touching the metallic !oints together. 4se the Fero nob on the front of the meter to adust the !ointer so it is aligned $ith the Fero !rinted on the +hms scale. +n $hich resistance range the sensitivity of the scale is the least ?i.e. cannot be Feroed@] Epa!n 'hy .
2. Determine the nominal value of the three resistors issued to your grou! by reading the color code. Record this nominal value in the table belo$. ". 4sing the analog multimeter ?*33@ as ohmmeter select a resistance range'multi!lier that for this resistor $ill !lace the needle some$here in the middle or right7side of the scale. 6ero the meter on this scale then measure the resistor value. Remember to re7Fero if you change scales. [ou $ill be able to accurately read the resistance to t$o signiBcant !laces $hy] nter!olate the third digit. Record the measured value of the resistors using able . *9LE
0esistors
RE%%*GCE +& D&&EREG RE%%+R% Color Code 0esistance FG Findicate 45band colorsG
Ra
Rb Rc
based on Color Code
0esistance FG based on AMM
, ) D# Measuring 6oltage using 6oltmeter
1. %et the function s$itch on the front of the *33 to DC voltage ?-DC@ and the range s$itch on the highest scale. 2. urn on the !o$er su!!ly and turn the out!ut voltage all the $ay u!. 9e careful to observe the !ro!er !olarity. ouch the *33 leads to the out!ut acs on the !o$er su!!ly as sho$n in &ig. 1. f the needle deXects the $rong $ay i.e. to the left instead of to the right the meter lead !ositions need to be reversed. %elect a scale that !laces the needle as high as !ossible on the scale $ithout !egging the needle. 3easure and record the ma=imum out!ut voltage of the su!!ly.
&igure 1. Connection bet$een !o$er su!!ly and analog multimeter set to - DC.
". urn the out!ut voltage all the $ay do$n and measure and record the minimum voltage this !o$er su!!ly can !roduce. f a &GE nob is available on your !o$er su!!ly unit turn this also to minimum. ,. Re!eat ste!s 2 and " to another !o$er su!!ly ?borro$ from the grou! beside you@. Record your results in the table belo$. Did you achieve the ideal minimum and ma=imum voltages] f not e=!lain $hy.
Po;er Supply Fm6G #%1
#%2
*9LE #+:ER %4##L[ -+L*(E% Ma%imum 6oltage Minimum 6oltage F6G
, C# !etermining 0esistance Using 6oltage and Current Measurements
1. %et the !o$er su!!ly to 10- then turn it oJ. %et u! the circuit sho$n belo$ on a !rotoboard using R1 1` and R2 5.1`.
&igure 2. %im!le circuit setu!.
Dra$ the circuit including the multimeter $hich you $ill use to measure the voltage across R2 and e=!lain $hy you thin this $ill $or. 2. %et the function s$itch on the *33 to read DC voltage ?DC-@ and the scale s$itch to the range a!!ro!riate for measuring 10-. urn on the !o$er su!!ly and then measure the voltage across the resistor R2. ae note of the voltage !olarity before taing your measurement. f you don8t get a reading chec your connections carefully. Record the actual voltage to three signiBcant Bgures. Dra$ the circuit including the multimeter $hich you $ill use to measure the current through R2 and e=!lain $hy you thin this $ill $or. ". %et the function controls on the *33 to read DC am!eres ?DCm*@. %tart $ith the scale s$itch set to the highest scale. +ne ste! at a time change the range s$itch so that more sensitive current scales are selected. f the needle O!egsQ at the u!!er end of the scale uicly s$itch bac to the ne=t higher scale. Read the current indicated on the meter and record this value. ,. 4sing the measured values for the voltage across and the current through this resistor com!ute the !o$er dissi!ated by the resistor R2. %ho$ your solution.
!# Computing 0esistance and Error
n !revious sections of this e=ercise you determined the value of the resistor by direct measurement using the ohmmeter and by reading the color code. n this section you $ill compute the actual resistance using +hm8s la$ and com!are the results. Sho; all solutions# 1. Re!lace R2 $ith each resistor used in #art * one at a time. :ith the measured values of the voltage and current obtained using ste!s C.2
and C." solve for the resistance R2 using +hm8s la$. Record the measured and com!uted values in able .
5 0 *9LE 4%G( +I38% L*: + 3E*%4RE RE%%*GCE ? @
0esistors
? @
0esistance of 0) FG
computed using 8hm@s La;
Ra Rb Rc
2. &or the follo$ing error calculations assume that the resistance value determined using the ohmmeter in #art * is the actual value of the resistor R2. Com!ute error bet$een the measured and nominal'true ?color code@ value using the euation U
100U
". Re!eat these error calculations for the com!uted resistance of D.1 as the actual value. Record these values and tabulate the results by creating able -.
0esistors
0esistance FG Color Code
*9LE ERR+R C*LC4L*+G% 0esistance FG 8hmmeter ?U@
0esistance FG 8hm@s La;
?U@
Ra
Rb Rc ,. E=!lain the !ossible origins of any error in these resistance values.
E# Po;er 0atings
1. 4sing the &ig. 2 but this time using R1 100` and R2 50` compute for the voltage across current through and the !o$er dissi!ated by each of the resistors. %ho$ solutions. 2. Re!lace R1 $ith 1` resistor. Com!are $ith the !revious case in terms of !o$er ratings. E=!lain using circuit analysis.
5 1
Electrical Measurements Laboratory EEE 34 Game> YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY %tudent Gumber> YYYYYYYYYYYYYYYYYYYYYYYYYY %ection> YYYYYYYYYYYYYYYYYYYYYYYYYY Date> YYYYYYYYYYYYYYYYYYYYYYYYYY E%periment & FPre5LabG !ebugging Circuits
#ut a chec on the bo= if the corres!onding tas is accom!lished. *. *ccom!lish and submit the %tudent nformation Card ?%C@ &ound in EEE ", %tudent Laboratory 3anual\ 9. Read and understand %ection Connectivity'Continuity est ;
%ection #otentiometer ; %ection 2."." #rotoboard'9readboard %ection ".1 heory and #ractice %ection 2.1.5 Eui!ment Calibration and %ection 2.".".2 Debugging'roubleshooting Circuits section's if a!!licable.
;11<
A $ith all their sub7
Do'ans$er the follo$ing ?indicate all references used@> 1. :hat is a light7emitting diode ?LED@] 9rieXy discuss its o!eration. nclude diagrams.
2. %ome students fear to vary or t$ea the circuit against to $hat is !rovided in the instructional schematic diagram. his fear originates from !ossible corres!onding costs and conseuences to damage to com!onents and eui!ment !ro!erties. Io$ever this fear serves as a barrier $hy many students cannot learn ho$ to debug circuits. n your o$n o!inion e=!lain ho$ you $ill overcome this fear]
0E$E0E>CE S<
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Electrical Measurements Laboratory EEE 34 (rou! Gumber'Letter> YYYYYYY 3embers> YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY Date> YYYYYYYYYYYYYYYYYY YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY %ection> YYYYYYYYYYYYYYYYYY YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY
E%periment &< !ebugging Circuits I#
8DEC"I6ES a@ o recogniFe the e=istence of a !roblem in a non7$oring circuit. b@ o determine the nature of the said !roblem. c@ o debug circuits in a systematic manner.
II#
MA"E0IALS N EKUIPME>" ?1@ !rotoboard ?1@ single !o$er su!!ly
?1@ analog multimeter ?*33@ ?1@ 555 C connectors cli!s and !robes III#
?"@ 1` resistor ?1@ ,/0D` resistor ?1@ red LED ?1@ green LED ?1@1u& ca!acitor
P08CE!U0E
Connecti!it&/Continuit& 'est 3ost if not all !roblems encountered in a non7$oring circuit are due to !oints that no longer form electrically continuous connections. he causes may not be observable or easily identiBable $hen the !roblem arises. %ome of the !ossible causes include> a blo$n7u! fuse or com!onent corroded connectors disconnected or faulty $ires loose connections or sim!ly an unintended o!en circuit.
Constructing circuits usually overloos a very im!ortant assum!tion A that all $ires and connectors are "ood. 4sing a bad $ire can be troublesome es!ecially if used in a com!le= circuit. hus it is a good !ractice to chec all $ires and connectors Brst before using them in constructing circuits. 1. %et the analog multimeter ?*33@ in ohmmeter mode. he multi!lier setting is immaterial. (et Bve ?5@ connecting $ires Bve ?5@ connector cli!s t$o ?2@ !o$er su!!ly cli!s one ?1@ oscillosco!e !robe and one ?1@ signal generator !robe. Label each connector. 2. 4se connectivity'continuity test to chec if each connector is either good or bad. * 0` reading ?or even if the needle deflects to the 0` direction@ indicates a good or connected condition. Construct a table and record the status of each connector. ". 4se connecting $ires and connectivity test to verify the connected !orts on a !rotoboard. Dra$ the !rotoboard and indicate $hich grou! of !orts ?e.g. ro$ column@ are connected.
5" . 'heoretical and Practical Measurements 1. %et the !o$er su!!ly to 10- then turn it oJ. %et u! the circuit sho$n belo$ on a !rotoboard using R1 R2 1`.
&igure 1. heoretical and !ractical measurements.
2. t is very useful to determine Brst the theoretical signal values in a circuit before inter!reting if acuired measurements are erroneous or not. n other $ords the actual values should guide the e=!erimenter if the data being gathered are valid or not. &rom the circuit $hat are the theoretical voltages across the !o$er su!!ly R1 and R2] ". 4sing a voltmeter -dc measure the voltage across the !o$er su!!ly R1 and R2. abulate your results. Did you get measurement values close to the actual ones] f not e=!lain $hy. ,. #ut another resistor R" 1` in !arallel $ith R2. Re!eat ste!s 9.2 and 9.". C %imple Circuit to 'est i a Component is 0or(ing Properl& 1. Construct the circuit sho$n in &igure 2. 4se R 1` -s 10- and t$o diJerently7colored LEDs for D1 and D2. he diagram for LED is also !rovided.
&igure 2. %im!le circuit. ;0b71<
2. *ssuming your $iring is correct and all LEDs are in good condition only one LED should be lit. :hich one ?D1 or D2@] 3easure the voltages -in and -out using a voltmeter -dc. ". Go$ reverse the !osition of both D1 and D2. :hich LED is lit at this moment] Gote that this !rocedure tests if an LED is $oring or not. Io$ever there are easier and more creative $ays to chec the condition of an LED. his
is ust one $ay to demonstrate testing of com!onents using a sim!le circuit.
5, 1 Comple2 Circuit 1. Construct the circuit sho$n in &igure ". he 555 C !in7outs is sho$n in &igure ,. his circuit emulates the trac lights $e see in the streets. 3ae the circuit $or and call the attention of your instructor once done. he dots indicate connected nodes and Ku*ps are not connected nodes.
&igure ". &lashing LED circuit. ;0b72<
&igure ,. 555 C !in7outs. ;0b7"<
2. %etu! your circuit su!!osing that you OcarelesslyQ constructed it ?i.e. it should not function !ro!erly@. t might be $rong $iring diJerent com!onents faulty $ires faulty com!onents etc. ". &ind a !artner grou! that is also Bnished $ith D.1 and D.2. E=change circuit'!rotoboard. Debug the circuit. Document ho$ your grou! debugged the circuit in a systematic manner. t $ould be easier to !rovide a ste!7by7ste! !rocess.
55 I6#
0EKUI0E! !ISCUSSI8>
1. here are some scenarios $herein connectors are continuous only in a certain orientation or !osition or $hen held t!"hty$oosey; or left hanging. :hat might this suggest] 2. %u!!ose the battery and light bulb circuit sho$n in &igure 5 failed to $or e=!lain ho$ you $ill use the d!v!de-and-con8uer a!!roach to debug the circuit. *t $hich !air of nodes $ill you start checing for voltage measurement] E=!lain.
&igure 5. 9attery and light bulb circuit. ;0b7,<
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Electrical Measurements Laboratory EEE 34 Game> YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY %tudent Gumber> YYYYYYYYYYYYYYYYYYYYYYYYYY %ection> YYYYYYYYYYYYYYYYYYYYYYYYYY Date> YYYYYYYYYYYYYYYYYYYYYYYYYY E%periment ) FPre5LabG !C Measurements FCurrentG
#ut a chec on the bo= if the corres!onding tas is accom!lished. &ound in EEE ", %tudent Laboratory 3anual\ Read and understand %ection 2.".2 D8*rsonval (alvanometer or 1m* 3ovement %ection "., Circuit7Level *nalysis of the 3ultimeter %ection ".,." DC *mmeter %ection ".,., DC -oltmeter %ection ".,.5 +hmmeter %ection 2.1.5 Eui!ment Calibration and %ection #otentiometer A $ith all their sub7section's if a!!licable. Do'ans$er the follo$ing ?indicate all references used@> 1. :hat is'are the DE*L characteristic's of a voltage source] +f a current source] 6oltage Source Current
Source
2. :hat is'are the DE*L characteristic's of an ammeter voltmeter and ohmmeter] Ammeter
6oltmeter
8hmmeter
". :hich of the meters ?ammeter voltmeter or ohmmeter@ need's an internal !o$er source to o!erate] :hich do'does not and $hy]
0E$E0E>CE S<
5 /
Electrical Measurements Laboratory EEE 34 (rou! Gumber'Letter> YYYYYYY 3embers> YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY Date> YYYYYYYYYYYYYYYYYY YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY %ection> YYYYYYYYYYYYYYYYYY YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY
E%periment )< !C Measurements FCurrentG I#
8DEC"I6ES a@ o no$ the diJerent methods of maing analog DC current measurements and to no$ $hen each method is a!!licable b@ o be able to s!ecify the degree of accuracy of any measurements made
II#
MA"E0IALS N EKUIPME>" ?2@ -ariable DC -oltage %u!!lies ?1@ 1m* 3ovement
?1@ #otentiometer 9o= ?1@ Digital 3ultimeter III#
?1@ *nalog 3ultimeter ?" !er value@ Resistors 100 Ω 1 Ω 10 Ω ?1@ Resistor 10720Ω #rotoboard Connecting :ires *lligator Cli!s
P08CE!U0E
1etermining the 3nternal Resistance o the 4m Mo!ement 1. Connect the circuit sho$n in &igure 1 $ith R2 disconnected and the !o$er su!!ly turned oJ. he voltage adustment nob of the !o$er su!!ly should be set to minimum ?fully counter7cloc$ise@.
2. urn the !o$er su!!ly on. %lo$ly increase -s using the voltage adustment nob. he 1m* movement needle should start to move u!scale. Continue increasing -s until the needle indicates full7scale ?1 m*@. ". Connect R2. 4se a 200 Ω or 500 Ω !otentiometer. ts initial setting is immaterial. Gevertheless once inserted the 1m* movement reading should decrease. *dust the shaft of R2 until the 1m* movement indicates half7scale ?0.5 m*@. ?f the current through the ammeter does not reach half7scale using the 200 Ω !otentiometer try a larger valued !otentiometer.@ ,. Disconnect R2. 3easure its resistance using an ohmmeter. he value measured $ill be a!!ro=imately eual to the internal resistance of the 1m* movement Rm.
. 5rrors in Current Measurements 1ue to 3nsertion 5fects 1. Refer to the circuit in &igure 2. &or each combination of -s and R in able com!ute for the value of the current I that should Xo$. 3ae sure that you are using the correct value for -s^ 4se a digital voltmeter if necessary. &ill out able corres!ondingly. *9LE C4RREG 3E*%4RE3EG% 6s F6G 0 FOG 3+ Ideal 3+ Measured using &mA movement FmAG FmAG 0.1 200 1 2 10 20
5 ) 2. &or each of these same combinations set u! the circuit of &igure 2 and measure the current that Xo$s by re!lacing the short circuit bet$een a and b $ith your 1m* movement. Com!lete able $ith your measured values. C 52tending the Range o the 4m Mo!ement 1. he full7scale range of a 1m* movement can be e=tended by connecting a shunt resistor across it as sho$n in &igure ". (iven no$ledge on the value of your Rm com!ute for the value of the shunt resistor Rsh that $ill e=tend the range of your ammeter from 1 m* to 10 m*.
2. 4se the scheme of &igure , to obtain a resistance $ith a value eual to that com!uted in #rocedure * above ?use a 10720 Ω resistor@. his setu! $ill act as your shunt resistance in &igure ". +r you can ust use a resistor $ith a value near to the one you com!uted in #rocedure C.1. ". %etu! the ne$ly7constructed 10m* movement. Chec its o!eration $ith the three calibration values indicated in able . *s sho$n in &igure " neglecting the internal resistance of the ne$ly7constructed 10m* movement you can vary the voltage su!!ly instead to obtain the calibration current values. &or e=am!le if -s 2- and R 1Ω in series then a 2m* current should Xo$ through the circuit. &ill u! the table corres!ondingly. *9LE CIECZG( IE +#ER*+G +& IE 10m* 3+-E3EG Corresponding Calibration &mA movement Current 0eading 0eading of Iu FmAG FmAG F!eectionG Oeasured Co*puted 2 , ) 10 Figure 1
&igure 1. Determining the internal resistance of the 1m* movement.
&igure 2. nvestigating insertion error in current measurements.
&igure ,. +btaining the reuired shunt &igure ". Ge$ly7constructed 10m* resistor. movement.
5 I6#
0EKUI0E! !ISCUSSI8>
ry to ans$er the follo$ing $hile you are inside the laboratory. %ome uestions can be ans$ered by further investigating the !rocedure stated above. 1. f $e are to measure the internal resistance of the 1m* movement $hy not use an ohmmeter right a$ay] %tate !ossible reasons. 2. %ho$ that the method used in determining the internal resistance of the 1m* movement is ust an a!!ro=imation. :hat is the internal resistance of your ammeter based on the !rocedure] *ssuming that the internal resistance you obtained is ty!ical of an ammeter sho$ that for the resistor R1 used in the !rocedure the a!!ro=imation has high accuracy. ". 9ased on the meter resistance of your 1m* movement !redict the accuracy that you should obtain for each of the measurements made in #rocedure 9. Com!are these Bgures $ith the actual accuracy of your measurements. *ccount for any diJerences. E=tend able ?or create a ne$ table@ to sho$ these Bgures. ,. %ho$ ho$ you com!uted for the value of Rsh to be used to convert your 1m* movement into a 10m* movement. :hat is the combined meter resistance of your 10m* movement] 5. Discuss the linearity and accuracy of the 10m* movement you constructed based on the calibration !oints given to you in able . :hat are the !ossible sources of error ?if there is any@]
0
Electrical Measurements Laboratory EEE 34 Game> YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY %tudent Gumber> YYYYYYYYYYYYYYYYYYYYYYYYYY %ection> YYYYYYYYYYYYYYYYYYYYYYYYYY Date> YYYYYYYYYYYYYYYYYYYYYYYYYY E%periment 3 FPre5LabG !C Measurements F6oltageG
#ut a chec on the bo= if the corres!onding tas is accom!lished. &ound in EEE ", %tudent Laboratory 3anual\ Read and understand again %ection 2.".2 D8*rsonval (alvanometer or 1m* 3ovement %ection "., Circuit7Level *nalysis of the 3ultimeter %ection ".,." DC *mmeter %ection ".,., DC -oltmeter %ection ".,.5 +hmmeter %ection 2.1.5 Eui!ment Calibration and %ection #otentiometer A $ith all their sub7section's if a!!licable. Do'ans$er the follo$ing ?indicate all references used@> 1. (iven the no$ledge on the o!eration of 1m* movement ?i.e. galvanometer@ e=!lain ho$ it can be used to measure voltage. E=!lain loading error in using this method.
2. E=!lain the !rinci!le behind ?voltage'current@ source transformation.
". E=!lain ho$ a !otentiometer can be used as a voltage divider. #rovide a circuit diagram.
0E$E0E>CE S<
1
Electrical Measurements Laboratory EEE 34 (rou! Gumber'Letter> YYYYYYY 3embers> YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY Date> YYYYYYYYYYYYYYYYYY YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY %ection> YYYYYYYYYYYYYYYYYY YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY
E%periment 3< !C Measurements F6oltageG I#
8DEC"I6ES a@ o no$ the diJerent methods of maing analog DC voltage measurements and to no$ $hen each method is a!!licable b@ o be able to s!ecify the degree of accuracy of any measurements made
II#
MA"E0IALS N EKUIPME>" ?2@ -ariable DC -oltage %u!!lies ?1@ 1m* 3ovement ?1@ #otentiometer 9o=
?1@ #rotoboard III#
?1@ *nalog 3ultimeter ;*33< ?1@ Digital 3ultimeter ;D33< ?" !er value@ Resistors 1 DΩ 10 DΩ 100 DΩ Connecting :ires *lligator Cli!s
P08CE!U0E
1etermining the 3nternal Resistance o the 4m Mo!ement 4se a digital multimeter set to ohmmeter and measure the internal resistance of your 1m* movement. Record its value. . 'he 1C Voltmeter using 4m Mo!ement 1. * DC ammeter can be used to measure voltage by sim!ly connecting a resistor in series $ith it as sho$n in &igure 2. Com!ute the value of the series resistance Rs that $ill enable your 1m* movement to measure DC voltages u! to 10 volts.
2. 4se the !otentiometer to obtain the resistance com!uted in ste! 1 above. %et u! your 10- full7scale voltmeter. Chec its o!eration $ith the three calibration values indicated in able . 4se the !o$er su!!ly for each calibration voltage value. &ill out able corres!ondingly. >8"E< [ou can use a standard resistor value if the internal resistance of 1m* movement is very lo$. *9LE DC -+L3EER 4%G( 1m* 3+-E3EG Calibratio &mA Movement Corresponding n
6oltage F6G 2 , ) 10
0eading F!eectionG
0eading of 6 u F6G
2 C 5rrors in Voltage Measurements 1ue to Loading 5fects 1. Refer to the circuit in &igure ". &or each of the values of R given in able com!ute for the value of -= that should be obtained. &ill out able corres!ondingly. 2. &or each of the values of R in able set u! &igure " and measure the voltage -= using your Kust constructed vot*eter ?see &igure 2@. &ill the measured values into able .
*9LE L+*DG( E&&EC% G -+L*(E 3E*%4RE3EG% 0 FOG "heoretical 6% F6G Measured 6% F6G 1 10 100
1 'he Potentiometer .ridge Method o Measuring Voltage 1. he !otentiometer bridge method can be used to mae voltage measurements $ith absolutely no loading eJect on the measured circuit. * !otentiometer bridge Nvoltmeter8 is sho$n in &igure ,. he DC su!!ly should be set to the desired full7scale voltage. he !otentiometer is adusted such that the resistance bet$een !oints : and J is initially Fero to avoid a reverse reading in your multimeter. * voltage measurement is made by> a. connecting terminals a S b to the unno$n voltage to be measured maing sure that !ro!er !olarities are observed b. adusting the !otentiometer until the 1m* movement reads Fero then c. disconnecting a S b and removing the !otentiometer from the circuit. d. measuring the resistance 0:J # *lso measure the resistances 0B: and 0BJ# he measured voltage should corres!ond to the value determined by voltage division.
2. Re!eat #rocedure C using the !otentiometer bridge method. &ill out able $ith your measurements. >8"E > %ince &igures " and , use the same voltage level ?10-dc@ you can in fact use a single DC su!!ly and im!lement them in !arallel.
0 FOG
1 10 100
*9LE L+*DG( E&&EC% G -+L*(E 3E*%4RE3EG% "heoretical 6% F6G 0:J FOG 0BJ FOG Corresponding 6% F6G
"
&igure 1. Determining the internal resistance of the 1m* movement.
&igure 2. DC -oltmeter to measure an unno$n voltage using the 1m* movement.
&igure ". nvestigating loading eJects in voltage measurements.
&igure ,. 3easuring an unno$n voltage using !otentiometer bridge techniue.
,
I6#
0EKUI0E! !ISCUSSI8>
ry to ans$er the follo$ing $hile you are inside the laboratory. %ome uestions can be ans$ered by further investigating the !rocedure stated above. 1. %ho$ ho$ you com!uted for the value of Rs to be used to convert your 1m* movement into a 10 - voltmeter. :hat is the internal resistance of your 10 - voltmeter] 2. 4sing a gra!h !lot the measured voltage Vreading ?y7a=is@ vs. calibration voltage Vcalibration ?=7a=is@ in able . n the same gra!h also !lot the ideal function Vreading 6 Vcalibration . Com!are the t$o !lots. Discuss the linearity and accuracy of the 10- voltmeter you constructed based on the calibration. :hat are the !ossible sources of error ?if there is any@] ". 9ased on the internal resistance of your 10- voltmeter !redict the accuracy that you should obtain for each of the measurements made in #rocedure C. Com!are these Bgures $ith the actual accuracy of your measurements. *ccount for any diJerences. E=tend able ?or create a ne$ table@ to sho$ these Bgures. ,. #rove that the measured voltage across a S b in #rocedure D is eual to the unno$n voltage being measured. :hy is there no loading eJect $hen this techniue is used to measure voltages] s this consistent $ith your results] *ccount for any errors. 5. :hat are the advantages and disadvantages associated $ith each techniue used to measure voltage in this e=ercise]
5
Electrical Measurements Laboratory EEE 34 Game> YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY %tudent Gumber> YYYYYYYYYYYYYYYYYYYYYYYYYY %ection> YYYYYYYYYYYYYYYYYYYYYYYYYY Date> YYYYYYYYYYYYYYYYYYYYYYYYYY E%periment 4 FPre5LabG 0esistance Measurements
#ut a chec on the bo= if the corres!onding tas is accom!lished. &ound in EEE ", %tudent Laboratory 3anual\ Read and understand again %ection 2.".2 D8*rsonval (alvanometer or 1m* 3ovement %ection "., Circuit7Level *nalysis of the 3ultimeter %ection ".,." DC *mmeter %ection ".,., DC -oltmeter %ection ".,.5 +hmmeter %ection 2.1.5 Eui!ment Calibration and %ection #otentiometer A $ith all their sub7section's if a!!licable. Do'ans$er the follo$ing ?indicate all references used@> 1. &rom the !revious e=!eriments $hat !ractical issues have you learned so far]
2. Do these change the $ay you vie$ theories in circuit analysis] f yes ho$] +ther$ise $hy]
". %tate !ossible !recautions in using an ohmmeter.
0E$E0E>CE S<
Electrical Measurements Laboratory EEE 34 (rou! Gumber'Letter> YYYYYYY 3embers> YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY Date> YYYYYYYYYYYYYYYYYY YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY %ection> YYYYYYYYYYYYYYYYYY YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY
E%periment 4< 0esistance Measurements I#
8DEC"I6ES a@ o no$ the diJerent methods of measuring resistance b@ o no$ $hen each method can be a!!lied c@ o be able to s!ecify the accuracy of any measurements made
II#
MA"E0IALS N EKUIPME>" ?1@ -ariable DC %u!!ly ?1@ 1 m* 3ovement 20` ?1@ Digital 3ultimeter ?1@ *nalog 3ultimeter Cli!s
III#
?1@ #otentiometer 9o=
?1 each@ Resistors Ra Rb Rc and 10` ?1@ 10` !otentiometer #rotoboard Connecting :ires *lligator
P08CE!U0E
'he %eries 7hmmeter Method 1. %et u! the circuit of &igure 1. %et the !o$er su!!ly to 10- and use a 10Z Ω !otentiometer for R2. 3ae sure that the !otentiometer is set to ma=imum and it reaches the indicated value ?or more@.
2. %hort together terminals a S b and adust R2 until the 1m* movement indicates full scale. Leave R2 at this setting. ". [our instructor $ill have available three resistors Ra Rb and Rc $hose resistances you are su!!osed to determine. Record into able the deXection D !roduced by each resistance in the 1m* movement $hen the resistance is connected to the circuit at terminals a S b. ? @
M ;01< 1
*9LE 0esistor Ra Rb Rc
%ERE% +I33EER 3EI+D !eection Corresponding 0esistance F!G 0eading FG
4sing the euation 0u 0o F& 5 !G! $here Ro Rm K R2 com!ute the corres!onding resistance readings and record these in able . . 'he Voltmeter - mmeter Method 1. he same resistances Ra Rb and Rc are to be determined using the circuit in &igure 2. 4se an analog multimeter as the voltmeter and the 1m* movement as the ammeter. Do not use the digital voltmeter ?D-3@ as the intended loading eJects $ill not be observed. -s may be set to any reasonable value !rovided that the 1m* movement does not go beyond
/
full7scale and the ma=imum !o$er rating of Ru ?unno$n resistor@ is not e=ceeded. n other $ords Ru should not get too hot $hile in the !o$ered circuit. &or each of the unno$n resistances connected in !lace of Ru record the readings of the voltmeter and the ammeter. &ill the readings into able .
0esistor
6s F6G
*9LE -+L3EER7*33EER 3EI+D * Ammeter 6oltmeter reading reading F6G FmAG
0u Ra Rb Rc ne"ect!n" oad!n" e@ects #ro* *eters
Corresponding 0esistance 0eadingQ FG
2. Re!eat the above !rocedure using the circuit of &igure &igure " to Bll in able able .
0esistor
6s F6G
*9LE -+L3EER7*33EER 3EI+D 9 6oltmeter Ammeter reading
0u reading F6G FmAG Ra Rb Rc ne"ect!n" oad!n" e@ects #ro* *eters
Corresponding 0esistance 0eadingQ FG
C 'he 0heats 0heatstone tone .ridge .ridge Method Method 1. he :heatston :heatstone e bridge bridge method is a !o!ular !o!ular method method of measurin measuring g resistance resistance !artic !articula ularly rly in the Beld Beld of instru instrumen mentat tation ion.. &igure igure , sho$s sho$s a :heats :heatston tone e bridge circuit. %et u! the circuit in &igure ,. 4se a !otentiometer for R". Let R1 10 and R2 20. -erify that the !o$er rating ?0.25 :@ of R1 and R2 are not e=ceeded even $ith a source voltage of 20-. 4se the voltmeter mode of the analog multimeter. 3ae sure of the !olarity. 2. 9efore turning the !o$er on the !otentiometer R" should Brst be set to
ma=imum ma=imum ?for minimum minimum !o$er !o$er dissi!ation dissi!ation@. @. Choose Choose the !otentiome !otentiometer ter $ith the greatest resistance value. $o measurements $ill be made for each unno$n resistance one $ith -s 5 volts and another $ith -s 10 volts. he voltmeter should be initially set to be able to read the ma=imum imba imbala lanc nce e of the the brid bridge ge $hic $hich h is -s. -s. #o$er o$erin ing g u! the the cir circuit cuit the the voltmeter must be able to read a #+%-E voltage. ". he value of Ru can be determined determined from the values values of R1 R2 and R" if the
bridge is balanced. he obective therefore is to get the bridge balanced by adust adusting ing the !otent !otentiom iomete eterr until until the voltme voltmeter ter reads eads Fero Fero ?or the lo$e lo$est st you you can can get get sinc since e the the !ote !otent ntio iome mete terr has has limi limite ted d adu adust stme ment nt resolution@. Decrease the eJective resistance of R" until you get a Fero. f you are having a hard time obtaining a null use the ne=t lo$er value of the !otentiometer. Remember to set Brst the eJective R" to the highest resistance resistance setting before adusting the nob.
,. &or each of the resistances Ra Rb and Rc tae note of the resistance R"
that balances the bridge for each of the !o$er su!!ly settings s!eciBed in C.2 above. his can be done by disconnecting R" from the circuit and measuring the resistance on the !otentiometer. &ill the obtained values into able -. 4se a digital multimeter.
) *9LE :IE*%+GE 9RD(E 3EI+D 0esistor 0u 03 FG at 6s 03 FG at 6s ,6 &-6 Ra Rb Rc 5. *ns$ *ns$er er the the reui euirred discu discuss ssio ion n ues uesti tion on _ befo beforre asi asing ng the the actu actual al values Ra Rb and Rc from your instructor. Do the values obtained mae sense]
&igure 1. %eries ohmmeter method
&igure ". -oltmeter7ammeter method 9
&igure 2. -oltmeter7ammeter method *
&igure ,. :heatstone bridge method
I6#
0EKUI0E! !ISCUSSI8>
ry to ans$er the follo$ing $hile you are inside the laboratory. %ome uestions can be ans$ered by further investigating the !rocedure stated above. 1. %ho$ that the relationshi! bet$een unno$n resistance Ru and deXection D for the series ohmmeter circuit of &igure 1 is given by> Ru Ro ?1 7 D@'D $here Ro Rm K R2 M D ? I m*@'?1m*@ n our case $hat is the value of Ro] :hy $as it not necessary to measure the value of R2 to be able to determine the value of Ro] 2. 4se the euation given in -.1 above to determine the values of Ra Rb and Rc. reat these as your e=!erimental results. Com!are these $ith the actual values of Ra Rb and Rc given by your instructor. >8"E> Let the color codes corres!ond to their theoretical values. *ccount for any diJerences. E=tend able ?or create a ne$ table@ to sho$ your results. ". &rom the voltage and current readings obtained in #rocedure 9 com!ute the corres!onding resistance values of Ra Rb and Rc both for the circuit of &igure 2 and the circuit of &igure ". Geglect the loading eJect of the meters. Com!are these $ith the actual values of Ra Rb and Rc. abulate your results. *ccount for any diJerences obtained. ,. &rom the voltage and current readings obtained in #rocedure 9 re7
com!ute the corres!onding resistance values of Ra Rb and Rc taing into account the loading eJect of the meters. Io$ do these com!are $ith the !reviously com!uted values and $ith the actual values of Ra Rb and Rc] 5. (iven
the t$o !ossible arrangements for maing resistance measurements using the voltmeter7ammeter method $hen should one method be used instead of the other if the resistance is to be taen as the voltage reading divided by the current reading]
. Derive the relationshi! bet$een R1 R2 R" and Ru for the :heatstone
bridge circuit of &igure , under balanced conditions. /. aing into account the tolerances of the resistances used in the bridge
com!ute for the range of !ossible values of Ra Rb and Rc from the values of R" obtained in #rocedure C. Do the actual values of Ra Rb and Rc fall $ithin the com!uted ranges] ). :hat $as the actual eJect of varying the !o$er su!!ly voltage on the
resistance measurements made using the :heatstone bridge method] :hat should the actual eJects have been] . Com!are the three methods of maing resistance measurements taing
into consideration sim!licity cost s!eed accuracy of measuring eui!ment tolerance of resistances used and any other !oints that may be of interest.
/ 0
Electrical Measurements Laboratory EEE 34 Game> YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY %tudent Gumber> YYYYYYYYYYYYYYYYYYYYYYYYYY %ection> YYYYYYYYYYYYYYYYYYYYYYYYYY Date> YYYYYYYYYYYYYYYYYYYYYYYYYY E%periment ,5ad FPre5LabG Introduction to 8scilloscopes
#ut a chec on the bo= if the corres!onding tas is accom!lished. &amiliariFe $ith diJerent !arts of an analog oscillosco!e. [ou can use htt!>''en.$iiboos.org'$ii'#racticalYElectronics'+scillosco!es as a guide or start but not as a reference. &ound in EEE ", %tudent Laboratory 3anual\ Read and understand %ection 2.1.2 &unction'%ignal (enerator %ection 2.1." *nalog +scillosco!e and %ection 2.1., Digital +scillosco!e. Do'ans$er the follo$ing ?indicate all references used@> 1. :hat is an oscillosco!e]
2. :hat are the uses of an oscillosco!e]
". ell the diJerence bet$een analog and digital oscillosco!e.
,. (iven a sinusoidal signal e=!lain the am!litude freuency and !eriod through illustration.
0E$E0E>CE S<
/ 1
Electrical Measurements Laboratory EEE 34 (rou! Gumber'Letter> YYYYYYY 3embers> YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY Date> YYYYYYYYYYYYYYYYYY YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY %ection> YYYYYYYYYYYYYYYYYY YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY
E%periment ,5a< Introduction to 8scilloscopes FAnalogG I#
8DEC"I6ES a@ o fami familia liari riFe Fe the the stud studen entt $ith $ith the the o!er o!erat atio ion n of a trigg trigger ered ed s$ee s$ee! ! oscillosco!e. b@ o be able to mae mae basic measureme measurements nts using an oscillosco!e
II#
MA"E0IALS N EKUIPME>" ?1@ Dual race race riggered riggered %$ee! +scillosco!e +scil losco!e ?1@ %ignal (enerator
III#
P08CE!U0E
G+E> Got all oscillosco!es in the laboratory are of the same brand'version. -arying a setting may vary from one to another ?e.g. !ulling a nob instead of rotating etc.@. Gonetheless the basic nobs ?and functionalities@ should be !resent on the front !anel of any oscillosco!e. he student is e=!ected to familiariFe him'herself $ith diJerent oscillosco!e interfaces in the laboratory. laboratory.
Part &? In!t!a /ett!n"s #or /!n"e race race 2perat!on 9efore turning the !o$er on set the oscillosco!e as instructed belo$. 1!spay /yste* Contros? %et the I>"E>SI"J a!!r a!!ro o=ima =imate tely ly e=tremes.
half half$a $ay y
bet$ bet$ee een n
,ert!ca /yste* Contros? %et the vertical mode to Channe &. %et %et the the Channe & 68L"S!I6 selector s$itch to the least sensitive !osition ?fully countercloc$ise@. he 6A0 contr control ol nob of the 68L"S!I6 s$itch ?usually at the center of the -+L%'D- selector s$itch@ should be in its calibrated detent !osition ;fully !ressed fully coun counte terrcloc cloc$ $is ise e ?or ?or cloc cloc$ $is ise@ e@ unti untill it loc locs7 s7di dirrecti ection on de!ends on the location of O CALQ the calibrated !osition< %et the Channe & in!ut cou!ling to 7>!. Gote> %ome oscillosco!es label their vertical channels Channe A B or Channe Q Q H instead of Channe Channe & S .
5or!6onta /yste* Contros? %et the SEC!I6 ?or 3*G 3E'D-@ s$itch to 0.5 ms.
he 6A0 control nob of the SEC!I6 s$itch ?usually at the cent center er of the the %EC' %EC'D D- sele select ctor or s$it s$itch ch@@ shou should ld be in its its calibrated = 1 detent !osition.
r!""er /yste* Contros? %et the trigger mode to AU"8. %et the trigger source to Channe & ?internal@. %et the trigger slo!e to R.
/ 2 Part ? he 1!spay /yste* Contros 3ae sure the line voltage setting on the oscillosco!e is correct before turning on the !o$er. urn the oscillosco!e on and allo$ it to $arm u! for a!!ro=imately "0 seconds. Locat!n" the Bea*? * horiFontal line should a!!ear on the screen. [ou may have to use the Channe & vertical P8SI"I8> control nob to locate the line. #osition the line at the center of the screen screen.. 4se the horiontal P8SI"I8> contr control ol nob nob to horiFo horiFonta ntally lly cente centerr the trace trace.. ry to e=!lore the e=treme !ositions using these nobs. Return the beam bac to the center of the screen. Focus? he trace you have on the screen screen may be out of focus. 3ae it as shar! as !ossible $ith the $8CUS control. Intens!ty? %et the brightness or illumination to a level comfortable to you. Refrain from setting the screen too bright to !reserve the screen ?i.e. mae it last longer@. race
Part )? he ,ert!ca /yste* Contros Connect the base of a !robe to the Channel 1 vertical in!ut connector. connector. f the !robe has an adustable attenuation set it to = 10. Co*pensat!n" the Probe? %et the Channe & 68L"S!I6 s$itch so that the oscillosco!e dis!lays 0.2 volts'divisio volts'division. n. 3ae sure the 6A0 control nob is in its calibrated detent !osition. Remember that you are using a =10 !robe. ?(enerally you $ould have to multi!ly the -+L%'D- indication by 10 to get the correct calibration.@ %et the channe & input coupling coupling to *C. Connect the !robe ti! to the P08DE A! terminal ?on some oscillosco!es this is the CAL terminal@ !rovided on the oscillosco!e. f the signal is too small adust the -+L%'D- nob such that your signal is at least 1 maor division !ea7to7!ea ?i.e. from minimum to ma=imum@. f the signal signal on the screen screen is not steady adust the trigger LE6EL control until the signal stabiliFes. f the signal still does not stabiliFe adust the SEC!I6 nob and then the trigger LE6EL control until you stabiliFe your signal. Dis!lay 27" cycles of the signal.
1. Dra$ Dra$ the e=act e=act $ave sha!e sha!e that a!!ear a!!ears s on the scre screen. en. %ho$ %ho$ ho$ the dis!lay a!!ears in relation to the graticule marings on the oscillosco!e face. ?he $ave that a!!ears on the screen should be !erfectly suare. f it is not a scre$driver adustment should be made on the com!ensation bo= at the base of the !robe until a suare $aveform $aveform is obtained.@
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2. %et the probe to =1. Choose an a!!ro!riate 68L"S!I6 setting such that the $hole $aveform is visible. Dra$ the e=act $aveform and indicate the 68L"S!I6 and SEC!I6 used. :hat is the diJerence bet$een a =1 and a =10 !robe] :hat is the advantage of one over the other]
". :hy is com!ensation needed] :hat do you actually do $hen you com!ensate a !robe] Does an =1 !robe have to be com!ensated]
Contro!n" ,ert!ca /ens!t!v!ty? %et the !robe attenuation bac to =10 68L"S!I6 setting to 0.2 volts'div and SEC!I6 to 0.5 ms'div. *dust the Channe & vertical P8SI"I8> control nob to line u! the lo$er edge of the P08DE A! $aveform $ith the center graticule line.
,. Io$ many maor divisions is the height of the dis!layed $aveform] :hat is the corres!onding !ea7to7!ea voltage of the P08DE A! signal]
5. urn the Channe & 68L"S!I6 s$itch t$o clic sto!s to the right ?cloc$ise@. :hat is the ne$ Channe & scale factor]
. Io$ many maor divisions is the height of the dis!layed $aveform no$] s this consistent $ith the measurement made in , above]
/. :hat is the eJect of turning the 6A0 control nob of the 68L"S!I6 s$itch out of its detent !osition] :hat !ossible use could this nob have]
Return the 6A0 nob to its detent !osition. Coup!n" the /!"na? %et the Channe & in!ut coupling to 7>! and !osition the trace on the center graticule line.
/ , ). :ith the probe connected to the P08DE A! terminal s$itch the Channe & in!ut coupling to *C. :hat is the eventual !osition of the $aveform on the screen]
. s this true for all settings of the 68L"S!I6 s$itch]
10.Go$ s$itch Channe & in!ut coupling to DC. :hat ha!!ens to the dis!layed signal]
11.:hat is the diJerence bet$een *C and DC cou!ling] :hen should one be used in !lace of the other] ?4se the trigger level to stabiliFe the $aveform in case it is unstable@.
he ,ert!ca Oode Contros? Connect a !robe to the channe 7in!ut connector. Do not forget to set the !robe to =10 if it is adustable. %et the Channe 68L"S!I6 s$itch to 0.2 volts and the Channe 68L"S!I6 6A0 control nob to its calibrated detent !osition. %et the channe in!ut coupling to (GD.
%et the vertical mode to CI 2?channel 2@. he dis!layed signal $ill no$ come from the channel 2 connector. -ertically !osition the channel 2 trace to the center of the screen $ith the channe vertical P8SI"I8> control. %et the channel 2 cou!ling to *C and chec the com!ensation of the channel 2 !robe as you did $ith the channel 1 !robe. #lay around $ith the channel 2 controls as you did $ith the channel 1 controls to give you a feel for using channel 2. :ith both the channel 1 and channel 2 !robes connected to the P08DE A! terminal set their corres!onding in!ut cou!ling to *C and set also the vertical mode to !UAL "0ACE ?this corres!onds to either the C8P or AL" mode on other oscillosco!es@. he signals from both !robes $ill simultaneously a!!ear on the screen. 4se the vertical P8SI"I8> control of either channel to se!arate the traces. [ou may have to readust the I>"E>SI"J control to get the desired intensity. ry both the *L and CI+# modes. &or each mode adust the SEC!I - to a very slo$ setting ?counter7cloc$ise@ and observe ho$ the traces are made. ry to observe ho$ the 2 modes are diJerent.
/ 5 Part 4? he 5or!6onta /yste* Contro Oa!n" !*e Oeasure*ents? %$itch the vertical mode bac to CI 1 and dis!lay the P08DE A! signal at the center of the screen. 4se the horiontal P8SI"I8> control nob to adust the dis!lay until one rising edge of the dis!layed $aveform is aligned $ith the center vertical graticule.
12.Io$ many maor and minor horiFontal graticule marings is it to the ne=t rising edge of the $aveform] Io$ many seconds does this corres!ond to]
1".Change the s$ee! SEC!I6 setting to 0.2 ms. Io$ many graticule marings is one !eriod of the dis!layed $aveform no$] *re your t$o measurements consistent]
1,.%et the SEC!I6 s$itch bac to 0.5 ms. urn the 6A0 control nob of the SEC!I6 s$itch out of its calibrated =1 detent !osition. Io$ does this aJect the dis!lay] :hat are the !ossible uses of this nob]
Return the 6A0 control nob to its calibrated =1 detent !osition. 15.#ull the horiFontal !osition control nob ?on other oscillosco!es this corres!onds to !ulling the -*R control nob@ to magnify the s$ee! SEC!I6 ?=5 on some sco!es =10 on other sco!es@. :hat is the ne$ horiontal scale factor ?%EC'D-@]
1.Io$ many graticule marings is the !eriod of the dis!layed $aveform no$] s this consistent $ith your !revious measurements]
Part ? he r!""er /yste* /ope Contro? Restore the s$ee! SEC!I6 to =1 ?unmagniBed i.e. -*R returned to =1 detent@. 4se the oscillosco!e to dis!lay through channel 1 a 15 ZIF 2 volt !ea7 to7!ea sinusoidal voltage $ith no DC oJset. *dust the s$ee! s!eed ?%EC'D-@ so that t$o to three cycles of the $aveform are dis!layed. 3ove the trace to the right $ith the horiFontal #+%+G control until you can see the beginning of the trace.
1/. Dra$ the resulting traces as you vary the SL8PE control from R
to 5. Io$ does each setting aJect the dis!lay] E=!lain $hy.
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r!""er Leve and r!""er Oode? >8"E> rigger mode is in *4+
1).3ove the trigger LE6EL control bac and forth through all of its travel. Io$ does this aJect the start of the trace] :hy]
Gotice that $hile the signal might lose synchronism at some level control settings the trace never disa!!ears. 1.%et the "rigger Mode s;itch to G+R3*L. Go$ $hen you use the trigger LE-EL control to move the triggering !oint youll Bnd !laces $here the trace disa!!ears. E=!lain this diJerence in behaviour bet$een normal and auto triggering.
Reset the trigger mode to *4+. ncrease the 68L"S!I6 setting to the ne=t more sensitive !osition ?cloc$ise@. 20.3ove the trigger !oint using the trigger LE6EL control as you did in 1) above. :hich 68L"S!I6 setting allo$s the trigger level control nob to have a larger range of motion before the $aveform becomes unstable] f you do not !erceive any diJerence try an even more sensitive 68L"S!I6 setting.
21.s the trigger level a voltage level or a number of divisions
level] E=!lain.
1ua race r!""er!n"? %et the vertical mode to D4*L R*CE ?*L or CI+# on other oscillosco!es@. %imultaneously dis!lay the signal generator out!ut and the P08DE A! signal.
22. +nly one of the signals can be made stable using the trigger LE6EL control] :hich one and $hy] Does your sco!e have the ca!ability of maing the other trace a!!ear stable] E=!lain.
/ /
Eterna r!""er? Reset the sco!e for single trace Channel 1 o!eration and redis!lay the signal generator out!ut. Go$ set the trigger source to E.
2".Can the trace be stabiliFed using the trigger LE-EL control nob] :hy or $hy not] 2,.ransfer the channel ) probe to the E:" "0I77E0 in!ut connector ?this means that the 2 !robes are in !arallel $ith the signal source@. he dis!lay can no$ stabiliFe $hen the e=ternal trigger in!ut is connected to the signal source] :hy]
25.Does the trigger LE-EL control behave in the same manner as $ith internal triggering $hen the vertical sensitivity is increased] ?observed in 1@
2.n this case is the trigger level a voltage level or a number of divisions level]
2/.Do the SL8PE control and the mode *4+ and G+R3*L setting still behave in the same $ay]
L!ne r!""er!n"?
2).%et the trigger source to LGE. he dis!lay should destabiliFe. :hy]
2.Lo$er the signal generator out!ut freuency ?around 500 IF@ until the dis!lay stabiliFes. *t $hat freuency is a stable dis!lay achieved]
Continue lo$ering the signal generator out!ut. +btain four to Bve freuencies at $hich a stable dis!lay is obtained. "0.:hat signal freuencies can be dis!layed $ith stability $ith the trigger source set to line] :hy] :hat !ossible use could this feature have]
/) he follo$ing are em!ty grid scales that you can use in setching $aveforms.
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Electrical Measurements Laboratory EEE 34 (rou! Gumber'Letter> YYYYYYY 3embers> YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY Date> YYYYYYYYYYYYYYYYYY YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY %ection> YYYYYYYYYYYYYYYYYY YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY
E%periment ,5d< Introduction to 8scilloscopes F!igitalG I#
8DEC"I6ES c@ o fami familia liari riFe Fe the the stud studen entt $ith $ith the the o!er o!erat atio ion n of a trigg trigger ered ed s$ee s$ee! ! oscillosco!e. d@ o be able to mae mae basic measureme measurements nts using an oscillosco!e
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MA"E0IALS N EKUIPME>" ?1@ Dual race race riggered riggered %$ee! +scillosco!e +scil losco!e ?1@ %ignal (enerator
III#
P08CE!U0E
G+E> Got all oscillosco!es in the laboratory are of the same brand'version. -arying a setting may vary from one to another ?e.g. !ulling a nob instead of rotating etc.@. Gonetheless the basic nobs ?and functionalities@ should be !resent on the front !anel of any oscillosco!e. he student is e=!ected to familiariFe him'herself $ith diJerent oscillosco!e interfaces in the laboratory. laboratory.
Part &? In!t!a /ett!n"s #or /!n"e race race 2perat!on
Lie all com!le= measuring eui!ment necessary settings have to be conBgured> +n the !isplay Menu set the 7rid setting so that the grid a!!ears on the dis!lay +n the Channel Channel 3enu i.e. C& and C) set the 6olts!iv setting to Coarse. %till on the Channel 3enu set the Probe setting to =1 by default.
/o*e convent!on on th!s docu*ent? Ma/or Ma/or division divisions s indicates indicates the large large graduation graduations s on the grid on the oscillo oscillosco sco!e !e screen screen $hile $hile minor divisions indicate the smaller graduations on the grid. he division !ertained on 68L"S!I6 or SEC!I6 are the maor divisions.
,ert!ca /yste* Contros? &ind the vertical controls on the sco!e. %et the vertical mode to Channe & by !ressing C&. #ressing it again sho$s the menu for Channel 1. t might also indicate $hich channels are active by lighting u! the button. Channe & 68L"S!I6 Fit is the vertical SCALE nob %et the Channe on most digital sco!es@ selector s$itch to the least sensitive !osition ?fully countercloc$ise@. countercloc$ise@.
%et %et the Channe & in!ut cou!l cou!ling ing to 7>!. Channel 1 in!ut Cou!ling can be accessed in the Channel 1 menu. Gote> %ome oscillosco!es label their vertical channels Channe A B or Channe Q Q H instead of Channe Channe & S .
5or!6onta /yste* Contros? &ind the horiFontal controls on the sco!e.
) 0 %et the SEC!I6 ?or ?or 3*G 3*G 3E 3E'D 'D-MM it is the the hori horiFo Font ntal al SCALE nob in most sco!es@ s$itch to 0.5 ms. r!""er /yste* Contros? &ind the trigger controls on the sco!e. +n the the trig trigge gerr menu menu do the the follo$ follo$ing> ing> o %et the trigge triggerr mode to E!7E. o %et the trigger s$ee! to AU"8. o %et the trigger source to Channe & ?internal@. o %et the trigger slo!e to ↑.
Part ? he 1!spay /yste* Contros Locat!n" the Bea*? * horiFontal line should a!!ear on the screen. [ou may have to use the Channe & vertical vertical P8SI"I8> control nob to locate the line. #osition the line at the center of the screen ?&or digital sco!es it is centered centered by default@. 4se the horiontal P8SI"I8> control nob to horiFontally center the trace. ry to e=!lore the e=treme !ositions using these nobs. [ou $ill notice that the !osition label #+% in the screen varies. Return the beam bac to the center of the screen. Part )? he ,ert!ca /yste* Contros Connect the base of a !robe to the Channel 1 vertical in!ut connector. f the !robe has an adustable attenuation set it to = 10. +n digital oscillosco!es you can adust the !robe attenuation on the !robe setting in the Channel 1 menu as you initially set. %ome !robes dont have an attenuation s$itch but has default attenuations such as =100 etc. Chec the label's on your !robe. Co*pensat!n" the Probe? Channe & 68L"S!I6 s$itc %et the Channe s$itch h so that that the oscillos oscillosco! co!e e dis!lays 0.2 volts'division. he volts'div setting can be checed via the CI1 label on the screen. screen. Rememb Remember er that you are are using a =10 !robe. !robe. %et the channe & input coupling to *C. Connect the !robe ti! to the P08DE A! terminal ?on some oscillosco!es this is the CAL terminalM mostly it is labeled by a suare $ave or !ulse $ith 2-!!@ !rovided on the oscillosco!e. f the signal is too small adust the -+L%'D-+L%'D- nob such that your signal is at least 1 maor division !ea7to7!ea ?i.e. from minimum to ma=imum@. f the signal on the scre screen en is not steady steady adust adust the trigger LE6EL control until the signal stabiliFes. Dis!lay 27" cycles of the signal by adusting the SEC!I6 nob.
1. Dra$ Dra$ the e=act e=act $ave sha!e sha!e that a!!ear a!!ears s on the scre screen. en. %ho$ %ho$ ho$ the dis!lay a!!ears in relation to the graticule marings on the oscillosco!e face. ?he $ave that a!!ears on the screen should be !erfectly suare. f it is not a scre$driver adustment should be made on the com!ensation bo= at the base of the !robe until a suare $aveform $aveform is obtained.@ 2. %et the probe to =1. Choose an a!!ro!riate 68L"S!I6 setting such such that that the the $hol $hole e $ave $avefo forrm is visi visibl ble. e. Dra$ Dra$ the the e=act =act $aveform and indicate the 68L"S!I6 and SEC!I6 used. :hat is the diJerence bet$een a =1 and a =10 !robe] :hat is the
advantage of one over the other] ?f your !robe doesnt have a =10 attenuation s$itch borro$ from other grou!s. hen return it after trying it out.@ ". :hy is com!ensation needed] :hat do you actually do $hen you com!ensate a !robe] Does an =1 !robe have to be com!ensated]
) 1
Contro!n" ,ert!ca /ens!t!v!ty? %et the !robe attenuation bac to =10 68L"S!I6 setting to 0.2 volts'div and SEC!I6 to 0.5 ms'div. f you do not have an attenuation s$itch you can use the !robe attenuation setting on the Channel 1 menu to mae it =10. f your !robe has an attenuation s$itch mae sure that the !robe setting in the sco!e is at =1 so that you can use the =10 attenuation on your !robe.
*dust the Channe & vertical P8SI"I8> control nob to line u! the lo$er edge of the P08DE A! $aveform $ith the center graticule line. ,. Io$ many maor divisions is the height of the dis!layed $aveform] :hat is the corres!onding !ea7to7!ea voltage of the P08DE A! signal]
ConBrm your estimate !ea7to7!ea voltage by using the measure function. Choose Measure 6oltage Pea25to5pea2# 5. urn the Channe & 68L"S!I6 s$itch t$o clic sto!s to the right ?cloc$ise@. :hat is the ne$ Channe & scale factor]
. Io$ many maor divisions is the height of the dis!layed $aveform no$] s this consistent $ith the measurement made in , above]
Coup!n" the /!"na? %et the Channe & in!ut coupling to 7>! and !osition the trace on the center graticule line.
/. :ith the probe connected to the P08DE A! terminal s$itch the Channe & in!ut coupling to *C. :hat is the eventual !osition of the $aveform on the screen]
). s this true for all settings of the 68L"S!I6 s$itch]
. Go$ s$itch Channe & in!ut coupling to DC. :hat ha!!ens to the dis!layed signal] 10.:hat is the diJerence bet$een *C and DC cou!ling] :hen should one be used in !lace of the other] ?4se the trigger level to stabiliFe the $aveform in case it is unstable@.
) 2
he ,ert!ca Oode Contros? Connect a !robe to the channe 7in!ut connector. Do not forget to set the !robe to =10 if it is adustable. %et the Channe 68L"S!I6 s$itch to 0.2 volts. %et the channe in!ut coupling to (GD.
%et the vertical mode to CI 2?channel 2@ only by turning oJ Channel 1. he dis!layed signal $ill no$ come from the channel 2 connector. -ertically !osition the channel 2 trace to the center of the screen $ith the vertical P8SI"I8> control. %et the channel 2 cou!ling to *C and chec the com!ensation of the channel 2 !robe as you did $ith the channel 1 !robe. #lay around $ith the channel 2 controls as you did $ith the channel 1 controls to give you a feel for using channel 2. :ith both the channel 1 and channel 2 !robes connected to the P08DE A! terminal set their corres!onding in!ut cou!ling to *C and turn on both channels. he signals from both !robes $ill simultaneously a!!ear on the screen. 4se the vertical P8SI"I8> control to se!arate the traces by !ressing the corres!onding channel you $ant to move and move it using the !osition nob.
Part 4? he 5or!6onta /yste* Contro Oa!n" !*e Oeasure*ents? %$itch the vertical mode bac to CI 1 ?turn oJ Channel 2@ and dis!lay the P08DE A! signal at the center of the screen. 4se the horiontal P8SI"I8> control nob to adust the dis!lay until one rising edge of the dis!layed $aveform is aligned $ith the center vertical graticule ?&or digital sco!es it is aligned by default@. 11.Io$ many maor and minor horiFontal graticule marings is it to the ne=t rising edge of the $aveform] Io$ many seconds does this corres!ond to]
ConBrm your estimate by using the measure function for "ime Period# 12.Change the s$ee! SEC!I6 setting to 0.2 ms. Io$ many graticule marings is one !eriod of the dis!layed $aveform no$] *re your t$o measurements consistent]
Part ? he r!""er /yste* /ope Contro?
4se the oscillosco!e to dis!lay through channel 1 a 12 ZIF 2 volt !ea7to7!ea sinusoidal voltage $ith no DC oJset !roduced by the function generator. *dust the %EC'D- so that t$o to three cycles of the $aveform are dis!layed.
) " 1".3ove the rigger LE6EL control nob bac and forth through all of its travel. Io$ does this aJect the start of the trace] :hy]
1,.Dra$ the resulting traces as you vary the SL8PE control from ↑ to ↓. Io$ does each setting aJect the dis!lay] E=!lain $hy.
Gotice that $hile the signal might lose synchronism at some level control settings the trace never disa!!ears. 15.%et the "rigger S;eep s;itch to G+R3*L. Go$ $hen you use the trigger LE-EL control to move the triggering !oint youll Bnd !laces $here the trace disa!!ears or freeFes. E=!lain this diJerence in behaviour bet$een normal and auto triggering.
Reset the trigger mode to *4+. ncrease the 68L"S!I6 setting to the ne=t more sensitive !osition ?cloc$ise@. 1.3ove the trigger !oint using the trigger LE6EL control as you did in 1" above. :hich 68L"S!I6 setting allo$s the trigger level control nob to have a larger range of motion before the $aveform becomes unstable] f you do not !erceive any diJerence try an even more sensitive 68L"S!I6 setting.
1/.s the trigger level a voltage level or a number of divisions
level] E=!lain.
1ua race r!""er!n"? %et the vertical mode to D4*L R*CE by turning on both channels. %imultaneously dis!lay the signal generator out!ut and the CAL signal.
1). +nly one of the signals can be made stable using the rigger control 2nob] :hich one and $hy] Does your sco!e have the ca!ability of maing the other trace a!!ear stable] E=!lain.
) ,
Eterna r!""er? Reset the sco!e for single trace Channel 1 o!eration and redis!lay the signal generator out!ut. Go$ set the trigger source to E.
1.Can the trace be stabiliFed using the trigger LE-EL control nob] :hy or $hy not]
20.ransfer the channel ) probe to the E:" "0I77E0 in!ut connector on the sco!e ?this means that the 2 !robes are in !arallel $ith the signal source@ and connect the !robe ti! to the signal generator out!ut as $ell. he dis!lay can no$ stabiliFe $hen the e=ternal trigger in!ut is connected to the signal source. :hy] f not try adusting the trigger nob to Bnd a stable signal.
21.Does the trigger LE-EL control behave in the same manner as $ith internal triggering $hen the vertical sensitivity is increased] ?observed in 1@ 22.Do the SL8PE ?↑ ↓@ control and the mode *4+ and G+R3*L setting still behave in the same $ay]
L!ne r!""er!n"?
2".%et the trigger source to LGE. he dis!lay should destabiliFe. :hy]
2,.Lo$er the signal generator out!ut freuency ?around 500 IF@ until the dis!lay stabiliFes. ?*dust the %EC'D- as $ell to dis!lay "7, !eriods of the trace@. *t $hat freuency is a stable dis!lay achieved] 25.Continue lo$ering the signal generator out!ut. +btain four to Bve freuencies at $hich a stable dis!lay is obtained. 2.:hat signal freuencies can be dis!layed $ith stability $ith the trigger source set to line] :hy] :hat !ossible use could this feature have]
)5 he follo$ing are em!ty grid scales that you can use in setching $aveforms.
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Electrical Measurements Laboratory EEE 34 Game> YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY %tudent Gumber> YYYYYYYYYYYYYYYYYYYYYYYYYY %ection> YYYYYYYYYYYYYYYYYYYYYYYYYY Date> YYYYYYYYYYYYYYYYYYYYYYYYYY E%periment . FPre5LabG AC !etection !iodes
Do'ans$er the follo$ing ?indicate all references used@> 1. :hat is a diode] E=!lain diode o!eration using its -7 characteristic.
2. :hat are the common uses'a!!lications of diodes]
". (iven a sinusoidal signal v?t@ $ith am!litude -s derive its average ?-ave@ and R3% ?-rms@ value.
0E$E0E>CE S<
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Electrical Measurements Laboratory EEE 34 (rou! Gumber'Letter> YYYYYYY 3embers> YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY Date> YYYYYYYYYYYYYYYYYY YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY %ection> YYYYYYYYYYYYYYYYYY YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY
E%periment .< AC !etection !iodes I#
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8DEC"I6E o ma=imiFe the oscillosco!es function as a tool in *C analysis MA"E0IALS N EKUIPME>" ?1@+scillosco!e ?" to ,@ alligator cli!s
?2 each@ 1D` and 10D` resistors ?1@ %ignal ?1@ Digital 3ultimeter ;D33< 1G,001 diode (enerator ?1@ ?1@ #otentiometer bo= ?1@ #rotoboard [email protected]& ceramic ca!acitor ?1@1m* ?1@ &ull $ave bridge movement rectiBer III#
P08CE!U0E
V-3 Characteristic o a 1iode 1. 4sing a digital multimeter at diode mode measure the eJective for$ard voltage ?6f @ of a conducting diode. Connect the !ositive terminal to the anode and the negative terminal to cathode. D33s usually dis!lay the diode voltage in m-. -f YYYYYYYYYYY m-
&igure 1. E=!loring the -7 characteristic of a diode. ;,71< 2. Refer on the Bgure above. Dis!lay both 6r and 6d in the oscillosco!e by using the dual dis!lay ca!ability. o dis!lay the correct voltage !olarity let probe A measure 6d and probe B measure 6r# #lace the negative terminals of !robe * and !robe 9 to po!nt n# his is a reuirement of the oscillosco!e dual dis!lay to have the !robes share the same ground in
order to achieve stable and synchroniFed dis!lay. #lace the !ositive terminal of !robe * to the ?K@ side of 6d $hile the !ositive terminal of !robe 9 at ?7@ side of 6r. [ou can insert the !robe !ins to holes of the breadboard. #ull the CI 9 !osition nob to I>6ert the signal
Diode -7 Characteristic
) ) ?!ush'latch button in some oscillosco!es@. his eJectively follo$s the !olarity based on the &igure 1. o vie$ the diode8s -7 characteristics set the oscillosco!e cou!ling to :5J and set the vertical mode to D4*L $ith both at 1-'div. %etch the Id ?y7 a=is@ vs 6d ?=7a=is@ characteristics of the diode. Gote that 6r is used to re!resent Id ?series conBguration@ since the current through the resistor is !ro!ortional to the voltage across it. 4se 6s &-6pp sinusoid &2.
. %ome 1iode Circuits
&our circuits sho$n in &igure 2 are diode7resistor and diode7ca!acitor combinations that demonstrate c!pp!n"; rect!Rcat!on; eve sh!#t!n" and Rter!n". >8"E< As2 your instructor to discuss the diTerences bet;een these four. 4se the sine $ave from the signal generator $ith freuency of 1 IF as the *C voltage source ?in!ut@ and adust the am!litude to , volts !ea7to7!ea no oJset. 4se R 1 ` and C 0.1 u&.
*ssuming an ideal in!ut voltage setch the out!ut voltage for each circuit ?the signal here no$ should >8" be inverted@. 4se "7, cycles of the out!ut $aveform. Ma2e sure to set the coupling to !C so that you $ill be able to vie$ if there are any voltage oJsets in the out!ut signals. his is essential so that you cannot mistae c!pp!n" $ith rect!Rcat!on. E=!lain $hat the circuit does ?i.e. its o!eration@. n addition observe $hat ha!!ens ;hen you reverse the diode ?no setches reuired for the reversed7 diode setu!@. Discuss your observations.
&igure 2. Diode circuits
Circuit >o# &
Circuit Go. 1 +!eration
)
Circuit >o# )
Circuit Go. 2 +!eration
Circuit >o# 3
Circuit Go. " +!eration
Circuit >o# 4
Circuit Go. , +!eration
>8"E< Defore proceeding ;ith the succeeding sections+ as2 your instructor to discuss the diTerence bet;een 6ave and 6rms# C 'he 8al * 0a!e 1etector 1. Com!ute for the value of Rs in the circuit of &igure " that $ill allo$ the 1m* movement to indicate a full scale reading $hen the su!!ly voltage -s is 10 -!ea ?this is euivalent to 20 -7!ea7to7!ea or 20-!!@. *ssume a sinusoidal in!ut voltage $aveform.
>8"E> he 1m* movement measures the avera"e current !assing through it.
0 2. %et u! the circuit using 1 IF in!ut. +btain Rs from a !otentiometer. he current reading in the 1m* movement should corres!ond to the level of !ea voltage from the in!ut hence a half?full@7$ave detector^ Chec the o!eration of your detector by com!aring its reading $ith the reading of the multimeter ?average voltage or -dc at the out!ut@ for the diJerent *C in!ut voltages from your signal generator. abulate your results.
*9LE I*L&7:*-E DEEC+R Pea2 6oltage &mA 6oltmeter movement 0eading 6s F6G 0eading FmAG at the 8utput F6dcG 10 ) 5 2
Computer 6s from 3m
". 4sing the oscillosco!e dis!lay -out $ith "7, cycles. Dra$ the $aveform. ndicate the volts'div and time'div settings used. 1 'he 9ull * 0a!e 1etector 1. Re!eat #rocedure C $ith the circuit in &igure ,. 4se the full7$ave bridge rectiBer. G+E> 9e careful in handling the full7$ave bridge rectiBer. he lead legs are fragile and bending't$isting too much can easily sna! a leg oJ. he full7$ave bridge rectiBer has , diodes inside. *9LE &4LL7:*-E DEEC+R Pea2 6oltage &mA 6oltmeter Computer 6s movement 0eading 6s F6G 0eading FmAG at the 8utput from 3m F6dcG 10 ) 5 2 5 Pea( 1etection 1. Com!ute for the theoretical value of Rs in the circuit of &igure 5 that $ill allo$ the 1m* movement to indicate the !ea value of -s $ith full scale range of 10 -. IG> :hat is the theoretical value of -out]
2. %et u! the circuit using 1 IF in!ut. +btain Rs from !otentiometer. Chec the o!eration of your detector by using it to measure the !ea values of the diJerent *C in!ut voltages from your signal generator. &or each reading record the 0MS value of the in!ut signal from the function generator as measured by a multimeter. abulate your results.
Pea2
0MS 6oltage of
*9LE #E*Z DEEC+R &mA 6oltmeter
Computer 6s
6oltage 6s F6G 10 ) 5 2
Input using 6oltmeter
movement 0eading at the 0eading FmAG 8utput F6dcG
from 3m
1 ". 4sing the oscillosco!e dis!lay -out $ith "7, cycles. Dra$ the $aveform. ndicate the volts'div and time'div settings used.
&igure ". Ialf7$ave detector circuit.
&igure ,. &ull7$ave detector circuit.
&igure 5. #ea7detector circuit.
2 I6#
0EKUI0E! !ISCUSSI8>
ry to ans$er the follo$ing $hile you are inside the laboratory. %ome uestions can be ans$ered by further investigating the !rocedure stated above. 1. Discuss ho$ a digital multimeter measures the voltage of a conducting diode. 2. Io$ do the voltage you obtained in #rocedure * com!are $ith those ty!ical for silicon diodes ?about 0./-@] ". Derive the relationshi! bet$een the ammeter reading and the am!litude of the in!ut for sinusoidal in!uts to the circuit of &igure ". &rom the relationshi! derive the euation that recalibrates the ammeter reading to indicate in!ut R3% voltage. ,. Io$ do the readings obtained by your half7$ave detector com!are $ith those readings obtained by the multimeter] :hat is the basic source of diJerence bet$een the t$o] s this consistent $ith your data] %uggest ho$ the relationshi! derived in _" above can be modiBed to achieve more accurate readings. :hat $ould your ammeter scale loo lie] 5. Derive the euation that recalibrates the ammeter reading to indicate in!ut R3% voltage for the full7$ave detector circuit of &igure ,. . Io$ do the readings obtained by your full7$ave detector com!are $ith those readings obtained from the multimeter] :hat is the basic source of diJerence bet$een the t$o] s this consistent $ith your data] /. :hat euation $as used to com!ute for the value of Rs in #rocedure E] Tustify using this euation. ). :hat are the advantages and disadvantages of full7$ave detection versus half7$ave detection] . &or each of the in!ut voltage in #rocedure E com!ute for the theoretical value of !ea voltage. ncor!orate these com!uted values in to your tabulated data. Io$ do these values com!are $ith the values you measured using your !ea detector] :hat is the basic source of error] 10.&or the !ea detector circuit of &igure 5 $hat is the ma=imum !ossible decay of the voltage across the ca!acitor taing into account the ca!acitance value and values of Rs and Rm] s this decay insigniBcant $hen com!ared $ith the full scale range of the !ea detector]
"
Electrical Measurements Laboratory EEE 34 Game> YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY %tudent Gumber> YYYYYYYYYYYYYYYYYYYYYYYYYY %ection> YYYYYYYYYYYYYYYYYYYYYYYYYY Date> YYYYYYYYYYYYYYYYYYYYYYYYYY E%periment 1 FPre5LabG AC Analysis 0LC Circuits
#ut a chec on the bo= if the corres!onding tas is accom!lished. Revie$ !hasor analysis for circuit net$ors involving R L and C. &ound in EEE ", %tudent Laboratory 3anual\ Read and familiariFe $ith !assive com!onents in %ections 2.2.1.2 Ca!acitors and 2.2.1." nductors. Do'ans$er the follo$ing ?indicate all references used@> 1.
2.
E=!ress ? @ cos?
K @ into its com!le= freuency domain ? @ using !hasor transformation.
Discuss ho$ to com!ute for im!edances 6 R 6L 6C. :hat is the relationshi! bet$een 6 L 6C and L C res!ectively]
0E$E0E>CE S<
,
Electrical Measurements Laboratory EEE 34 (rou! Gumber'Letter> YYYYYYY 3embers> YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY Date> YYYYYYYYYYYYYYYYYY YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY %ection> YYYYYYYYYYYYYYYYYY YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY
E%periment 1< AC Analysis 0LC Circuits I#
II#
8DEC"I6E o familiariFe the student $ith the basics of *C circuit analysis. MA"E0IALS N EKUIPME>" ?1@ Digital 3ultimeter ;D33<
?1@ Ceramic ca!acitor ?0.1u&@ ?1@ +scillosco!e ?1@ Resistor ?1Z`@ ?1@ %ignal generator ?1@ #rotoboard ?1@ ransformer ?secondary $ill serve as inductor@ *lligator cli!s and connecting $ires III#
P08CE!U0E
3mpedance o a Practical 3nductor 1. :ith the function generator and $ith the aid of the oscillosco!e !roduce a 10 volt ?!7!@ 0 IF sine $ave $ithout DC oJset ?this $ill serve as your su!!ly voltage -% in F!"ure &@. 2. 4se the secondary of the transformer as your inductor ?e.g. one end at 0-
and another end at 12-@. 3easure the resistance RL of this inductor using the D33. :ire u! F!"ure & using R 1Z` . 3easure R3% voltages values - -R and -6 using the -ac of the multimeter. -erify using the oscillosco!e ?the -!ea and -rms are related A note that $e have a sinusoidal signal@ ". Com!ute for the values of current the inductance L and the inductive
reactance L. *9LE 3#ED*GCE +& #R*CC*L GD4C+R Measured 6alues Computed 6alues 0L I 6" L 60 :L 6
. Ma(ing RM% Measurements 1. %et the function generator to 0 IF sinusoidal $aveform. Connect it to the multimeter. %et the multimeter to *C volts. 2. *dust the am!litude nob of the function generator until you get a multimeter reading of 5 -. 4se the oscillosco!e to dis!lay the generated signal. 3easure the am!litude of the voltage and the !eriod of the $aveform. :hat is the relationshi! of the voltage from the multimeter reading to the voltage measured using the oscillosco!e]
5 C :VL in C circuits C4 3nducti!e Circuits
Connect the oscillosco!e !robe as sho$n in F!"ure using the same source as in #*R *. 4se CI+# mode and invert the signal in CI*GGEL 2. *dust your -+L%'D- and 3E'D- settings to obtain a fairly large and $ide ?at least one to t$o !eriods@ $aveform. Dra$ the traces indicating the signiBcant !oints. nclude volts'div and time'div settings. 9y ho$ much does -R lag -6] n degrees ho$ much is this euivalent to] *dd the t$o traces using the *DD function of the oscillosco!e. Dra$ the trace indicating the signiBcant !oints. ae note of the am!litudes of the traces. :ith the use of a !hasor diagram sho$ that the sum of -R and -6 euals -. C; Capaciti!e Circuits
:ire u! F!"ure ) using R1Z` and C0.1u&. &or -% use / volt ?!7 !@ 1500 IF sine $ave $ithout DC oJset. 4se the -ERC*L mode in *L mode and invert the signal in CI*GGEL 2. *dust your -+L%'D- and 3E'D- settings to obtain a fairly large and $ide $aveform. Dra$ the traces indicating the signiBcant !oints. 9y ho$ much time does -R lead -C] n degrees ho$ much is this euivalent to] *dd the t$o traces using the *DD function of the oscillosco!e. Dra$ the trace indicating the signiBcant !oints taing note of the am!litudes of the traces. *gain using !hasor diagrams sho$ that the sum of -R and -C euals -.
I6#
0EKUI0E! !ISCUSSI8>
1. Discuss the calculations you !erformed in !art *.". 2. n !art 9.2 discuss the relationshi! bet$een the voltage reading in D33 ?in *C mode@ and the voltage measured using oscillosco!e. *re the actual measurements consistent $ith $hat you e=!ect theoretically] ". :hat is the relationshi! of the voltage from the multimeter reading to the voltage measured using the oscillosco!e] ,. *nalyFe and discuss your results in !art C.1 using the conce!ts you learned about the voltage and current relationshi!s in an inductive ?RL@ circuit. 5. *nalyFe and discuss your results in !art C.2 using the conce!ts you learned about the voltage and current relationshi!s in ca!acitive ?RC@ circuit.
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Electrical Measurements Laboratory EEE 34 Game> YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY %tudent Gumber> YYYYYYYYYYYYYYYYYYYYYYYYYY %ection> YYYYYYYYYYYYYYYYYYYYYYYYYY Date> YYYYYYYYYYYYYYYYYYYYYYYYYY E%periment FPre5LabG "ransducers and 8perational AmpliVers
Do'ans$er the follo$ing ?indicate all references used@> 1. :hat are transducers] :hat are the ty!es of transducer]
2. :hat are sensors and actuators] (ive e=am!les each.
". :hat is an o!erational am!liBer] Describe its basic o!eration using ideal condition.
,. :hat are the basic circuit to!ologies using o!erational am!liBers and their uses]
0E$E0E>CE S<
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Electrical Measurements Laboratory EEE 34 (rou! Gumber'Letter> YYYYYYY 3embers> YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY Date> YYYYYYYYYYYYYYYYYY YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY %ection> YYYYYYYYYYYYYYYYYY YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY
E%periment < "ransducers and 8perational AmpliVers I#
a@ b@ c@ d@ II#
III#
8DEC"I6ES Describe the o!eration and electrical characteristics of commonly7used transducers and sensors. #erform measurements using transducers sensors and electrical measurement circuits. *ccount errors introduced by non7ideal characteristics of the transducers and sensors on the measurements made. 4se o!erational am!liBer to condition the signal !roduced by transducers and out!ut corres!onding signal'indicators.
MA"E0IALS N EKUIPME>" ?1@ +scillosco!e ?1@ L3"5 Centigrade em!erature %ensor ?1@ %ignal ?1@ 4E,,/ GC hermistor generator ?1@ Digital ?1@ Light De!endent Resistor ?LDR@ multimeter ?2@ -ariable DC su!!ly ?1@ L&"5" +!erational *m!liBer
$ires and cli!s soldering iron ?5@ 1D` resistors ?1@ 10` !ot
P08CE!U0E
'hermistor 1. E=!ose the thermistor to ambient tem!erature ?about 25pC@. Do not touch the body of the thermistor itself. 2. Record the time it taes for the resistance reading to stabiliFe from the instant of !oint of contact. %table reading is $hen the measured value varies insigniBcantly. 3easure and record the resistance of the thermistor. ". #lace the thermistor in contact $ith the human body ?average normal body tem!erature is "/pC@. #lacing it bet$een the hands'Bngers is usually most convenient. Re!eat *.2. ,. #lug7in the soldering iron and $ait for about 27" minutes until it reaches its heating tem!erature ?about 120pC@H. #lace the ti! of the iron in contact $ith the body of the thermistor. 9e e=tra careful that the ti! touches +GL[ the thermistor. Re!eat *.2 then un!lug the soldering iron. 5. abulate your resistance measurements and !lot them against tem!erature.
. Com!are $ith datasheet values ?see *!!endi= 9> %ome Gotes from ransducer Datasheets@.
C*4+G> 9e ER* careful such that the soldering iron does not come into contact $ith anything not intended including yourself^ *
. LM<= Centigrade 'emperature %ensor 1. Connect the L3"5 sensor to a K5- DC single !o$er su!!ly and voltmeter to measure -out as sho$n on the right. D+49LE CIECZ [+4R C+GGEC+G% 9E&+RE 4RGG( +G IE #+:ER. 3ae sure the cli!s are not shorted $ith adacent !in'cli!s^ %et the voltmeter if not automatic to 2- DC scale. 2. Re!eat %te!s *.17*. but this time measuring the out!ut voltage of L3"5 instead of resistance.
C Light 1ependent Resistor )L1R+ 1. Connect the LDR to a digital ohmmeter. E=!ose the LDR to room or ambient lighting on your table and record its Oroom7lightQ resistance. 2. #artially cover the LDR to !revent some light from reaching it. Record its Oshado$Q resistance. ". Cover the LDR com!letely. t $ill hel! to use any blac material so as to !revent all light from reaching the LDR. Record its OdarQ resistance. ,. #lace the LDR near the room lights and record its OlightQ resistance. 5. #lot your results. 4se intensity of light on the =7a=is and the resistance on the y7a=is. !# 8perational AmpliVer used as 6oltage Comparator 0ECALL< o; to use negative !C supplyW Bho sets the =7>!HW
1. :ire7u! the circuit as sho$n on the left. #o$er u! using -ccK K5 -dc and -cc7 7 5 -dc
>8"E> +nly 1 o!7am! $ill be used A choose.
Let -com!are'ref be connected to ground ?essentially 0 -dc@ and -in "-!! 0-dc oJset 1IF sinusoidal signal. he schematic of L&"5" is as sho$n belo$ ?you can use either of the t$o o!7 am!s inside@.
he length7$ise center of the !rotoboard ?the canal7lie@ is designed to Bt com!onent !acages such as L&"5". 2. #robe both in!ut and out!ut signals $ith their Fero7levels overla!!ed. 4se DC cou!ling. 3ae sure the !robes have ground connection. Dis!lay the out!ut $ith t$o to three !eriods. Dra$ the $aveforms and state your observations. ". -ary the DC oJset of the in!ut signal in increment'decrement of 0.1-dc but not e=ceeding K'71.5-dc. +bserve $hat ha!!ens to the out!ut $aveform. ,. &rom your observations e=!lain ho$ the circuit o!erates as a voltage com!arator.
10 0 I6#
0EKUI0E! !ISCUSSI8>
ry to ans$er the follo$ing $hile you are inside the laboratory. %ome uestions can be ans$ered by further investigating the !rocedure stated above. 1. 9rieXy e=!lain the theory involved in the o!eration of each transducer used in this e=!eriment. 2. Com!are the thermistor and the LDR in terms of linearity sensitivity and res!onse time. :hat ty!e of a!!lications is each suited to and $hy] ". hin of and list do$n other a!!lications of the transducers used in this e=ercise. ,. Research on three ?"@ transducers not used in this e=!eriment and brieXy discuss the theory behind their o!eration and cite their a!!lications. 5. n #art D. $hat are the !ea levels of out!ut voltage] Io$ is this related to the su!!ly voltages -CCK and -CC7]
10 1
, !ocumentation *s mentioned in the !revious cha!ter and for em!hasis $e can say that !erforming e=!eriments is essential. (athering data and analysing S inter!reting them ho$ever are more valuable. Documenting re!orts is one of the maor obective of EEE ",. +ne must learn ho$ to re!ort data in an academic !ers!ective. n the Beld of EEE the most acce!ted format is the one !rovided by the largest !rofessional organiFation in the $orld A EEE. * sam!le format to be used for #ost7Lab documentation can be found in *!!endi= *> %am!le EEE #a!er for *, #age %iFe.
,#& !ocumentation 7uidelines he follo$ing guidelines $ill hel! the students in !roducing a com!lete readable and coherent re!ort. hese criteria are the eys to an eJective re!ort.
,#&#& "echnical !evelopment 1. f the e=!eriment ass for !ossible e=!lanations ?e.g. sources of error@ it is e=!ecting the students to thin and not ust enumerate. *ll !rocedure covered in these e=!eriments are governed by circuit theory. %im!ly !ut all e=!lanations should be baced7u! $ith a certain level of circuit theory and analysis. 2. &ollo$ing _1 e=!laining !roving and establishing claims through circuit analysis must be !resented $ith guiding euations and'or formulas $henever necessary. ". n re!orting the !rocedures done in the e=!eriment should not be re!eated $ord for $ord. t $ould hel! to summariFe it. he im!ortant things are the measurement results and discussion follo$ing it. ,. abulating data is not euivalent to !resenting data. ables $ould not s!ea for themselves. Conseuently mirroring the tabulated data into !aragra!h form is still not !resenting data. abulating data is for organiFation of measurement values and easier com!arison. #resenting data on the other hand is e=!laining the sense or the analysis behind those tabulated data. 5. n7de!th and further analysis in #ost7Lab re!orts can earn additional merit.
,#&#) Paper $ormat and Appearance 1. &ollo$ the recommended format ?see *!!endi= *> %am!le EEE #a!er for *, #age %iFe@. Do not include email addresses. 2. nclude grou! letter'number at the Brst !age on u!!er left corner. his hel!s the instructor for better tracing and easier grade recording. ". f you $ant to re7create or modify the circuit diagrams there are lots of circuit editor available for free online. +ne good e=am!le is the 1!a 1!a"ra* Ed!tor ?see http?$$d!a-!nstaer.de@. ,. #resent com!utations solutions and euations in a logical and !resentable $ay. Learn to use euation tools in your document !rocessor. 3ae the Bnal euations in bold7ty!e.
5. #resenting the uestion from NReuired Discussion8 and then follo$ed by the ans$er is allo$ed. #rovide number and italiciFed the uestions for better readability. . Do >8" use :ii!edia and other forum $ebsites as reference for academic !a!ers^ his is lie digging your o$n grave. /. t is >8" necessary to include the materials and eui!ment used in the re!ort.
10 2 ). *void hanging title subtitle or header. ?e.g. the title of a section and its Brst !aragra!h are cut through ne=t column'ne=t !age@. . Do not include the *cno$ledgment !art. t is >8" necessary for laboratory re!orts. 10.%ome are !rinting their re!orts not from their original machine. hus to avoid com!atibility bet$een document !rocessors of your o$n machine ?$here you edited your re!ort@ and the machine !rinting the Bnal !a!er it is a good !ractice to convert the Ble Brst to a #D& format. his $ill !reserve your intended format.
,#) 8nline Submission 7uidelines he #ost7Lab re!ort should be submitted in7!rint. Io$ever if there are certain events ?e.g. class sus!ensions etc.@ $here the instructor $ished to chec softco!ies instead then certain guidelines submitting the re!ort online should be follo$ed. o be fair $ith students deadline should be at least a $ee once the announcement for an online submission has been made.
&# Email Sub/ect $ormat 4se the follo$ing format as the email subect> ;V%ubectW V%ectionW< VReuirementW by V%urname1 %urname2 %urname"W
E=am!le> ;EEE ", 3CDE< #ost7Lab 5 by 9ernardo RamireF %alces t is im!ortant to follo$ this format since some emails may be treated as s!am and hence Bltered. )# Attachment $ile "ype 9y default use> i. Com!ressed Ble A if more than 2 Bles. ii. #D& A documents s!readsheets !resentations etc. iii. +r the Ble ty!e as directed by the instructor. 3# Attachment Sie Limit he attachment Ble siFe should not e=ceed 539. Com!ress the Bles and images as necessary. 4# Sender Address +nly one member in a grou! should be the sender !er reuirement. he Brst email sent $ith valid email subect $ill be considered as the submission. Go sending of version 2.0 modiBcations and the lie so mae sure that $hat you submit is Bnal. t is assumed that a grou! is $ell7coordinated. Go uestions directed to the instructor by grou!mate * if grou!mate 9 already submitted this and that. ,# 0ecipient Address 4se only the email address !rovided by the instructor. .# !eadline
f deadline is 11>5>00 #3 #% then late is 11>5>01 #3 #%. Late re!orts $ill never be acce!ted so better send as early as !ossible. Deadline e=tension is never an o!tion. 1# Kuestions *ny uestion about the reuirement should +GL[ be done in class or during consultation hours !rior to submission deadline.
10"
. Pro/ect he !roect is the ca!stone reuirement for EEE ",. *fter a!!lying the conce!ts learned in circuit theory into actual setu!s it is then time for students to sho$case their ability and sills in building and constructing something and Bnally mae it $or. his reuirement aims to give the students a fun and fulBlling e=!erience $ith electronics. his cha!ter $ill discuss the !roect guidelines and $ill enumerate most common uestions students as during !roect develo!ment.
.#& Pro/ect 7uidelines his section $ill guide the students in develo!ing their desired !roect from !ro!osal stage u! to Bnal !resentation. *s an em!hasis the !roect is to be accom!lished by grou!. he number of students in a grou! is deBned at the start of the semester ?!lease see Class #olicies@. [ou have the freedom to choose your grou!7mates for this tas.
.#&#& Pro/ect Proposal %tudents cannot start building their desired !roect $ithout the consent of the laboratory instructor. &rom the middle of the semester u! to a certain date about three to four $ees before F!nas 'ee the students can !ro!ose their desired !roect to!ic. he !roect !ro!osal does not have to be formal. Tust !re!are a detailed !rint7out of the circuit diagram for the desired !roect. t may hel! to !re!are multi!le !ro!osals to increase the chance of getting an a!!roved to!ic. he diculty of the desired !roect is to be assessed by the instructor. %tudents can in fact im!lement microcontroller7based !roects if they can. Io$ever the level of diculty should be ust enough to achieve the obective of this !roect. Reuest for a!!roval can be done through instructor8s consultation hours or during class hours. ae note that a certain to!ic can only be a!!roved once for the current EEE ", batch.
herefore to!ics are on a OBrst a!!rove Brst reserveQ basis. &ailure to get an a!!roved !roect to!ic until deadline may mean an automatic Fero for the !roect grade. #lease no$ the date and time for the deadline of !roect !ro!osal from the laboratory instructor. Go need to submit a formal !ro!osal !a!er once an a!!roval is acuired. *s a reference the follo$ing are some notable $ors from !revious EEE ", batches ?current students can im!lement similar but not the same !roect@> Eectron!c /tethoscope LE1 ,ot*eter /!*pe FO rans*!tter A!r Fo' Contro
Sa*e /ho' Buttons Ous!c to L!"ht Ooduator Eectron!c 1!e '$ T/o' 1o'nT &0-eve no!se !nd!cator
%tudents can visit the library to loo for boos $ith interesting electronics !roect or from reliable sources in the internet.
10 ,
.#&#) Pro/ect "esting and Construction he !roect should be im!lemented on !rotoboard only. Construction and testing can be done during class hours if the main agenda for the day is over. f there is no e=tra time then the class schedule should allot 27" $ees to give students time to construct their !roects before having the !roect !resentation. %tudents can al$ays chec the availability of needed com!onents $ith the nstruments Room ? see Append! 1@. ae note that buying of materials for this !roect reuirement is highl& discouraged . %tudents may be reuired by the instructor to sho$ u! in the laboratory during !roect construction ?e.g. for milestone checing@.
.# Pro/ect !ocumentation 9efore the actual start of !resentation of a grou! they should submit a !rinted ?not necessarily in coloured7!rint@ documentation of their !roect. n sim!le terms> no documentation+ no pro/ect grade# &ollo$ EEE format for *, siFe !a!er. he main !arts of the documentation must include> . .
. -.
Abstract ntroduction #roect Develo!ment *. Circuit Descri!tion 9. Circuit +!eration C. #roect Construction D. #roblems Encountered E. Delegation of ass &. List of 3aterials #roect *!!lications Conclusion 0eferences
.# Pro/ect Presentation *ll !ro!onents should be !resent at the date and time of !resentation. he grou! may o!t to !resent even before their assigned schedule once done $ith the reuirements ?e.g. students might $ant to focus more on maor subects near end of semester@. #resentation slides should not be fancy7themed and content should be as concise as !ossible. ime allo$ed !er grou! to !resent is )7 10 minutes only. his includes the demonstration follo$ed by S* for defense A ma=imum total of 15 minutes !er grou!. Go7sho$ grou! on the day of !roect !resentation $ill receive an automatic Fero ?0U@ grade for !roect.
10 5
.#&#, Criteria for 7rading he criteria for 100U !roect grading is> 0U Demonstration &unctionality :iring %etu! ;9*< 20U Documentation 20U Defense #resentation %lides uestion S *ns$er
?,5U @ ?10U @ ?5U@
?10U @ ?10U @
.#) $re*uently As2ed Kuestions F$AKsG 1. :hat are the available com!onents $e have in the nstruments Room] %tudents can borro$ ?and return after$ards@ their needed com!onents from the nstruments Room. *vailable com!onents can be checed in *!!endi= D> *vailable Com!onents in nstruments RoomQ. 2. Do $e need to borro$ again every time $e $ill test our circuit] [es. +r maybe not. t de!ends on the administrative rule im!lemented by the nstruments Lab technician. ". he s!eciBc com!onent $e need is not available in the nstruments Room nor in any electronics sho! locally. :hat shall $e do] Zno$ the function of the needed com!onent in the circuit. Loo for its datasheet online. &ind for e8u!vaent com!onent that can serve as a substitute. &or e=am!le 2G"0, is euivalent to 9C5,/ for a transistor. Gote that im!orting for a com!onent ?i.e. !urchasing online@ is not necessary. *side from being costly it $ill tae time to arrive. f that is the case better chan"e the !roect as advised by the instructor. ,. :e $ant to buy com!onents in an electronics sho!. ?Got a uestion@ +Z. t is u! to the students. Tust a !iece of advice A no$ Brst all the information you need before you go to any electronics sho!. #lan ahead.
Chec the datasheets of your needed com!onents. here might be euivalent com!onents. Chec if the store you are heading to have the com!onents you need. [ou can chec their list online or you can contact them.
+ther$ise you $ill ust $aste your time and eJort. :or smart not hard.
5. Io$ to determine the corres!onding !in7outs of the C'transistor] Chec the datasheet. . s it safe to use a DC su!!ly voltage in !lace of a battery] +f course.
10 /. s it safe to use a larger su!!ly voltage for our circuit] Chec the datasheets of all com!onents on absolute ma=imum ratings ?es!ecially !o$er ratings@. ). Can $e im!rove the design for our !roect im!lementation] f you thin it $ill im!rove your $or then feel free to do so. . :e are done $ith our !roect ?$ith documentation and !resentation slides@. Can $e !resent on an earlier date] [es. *nytime $ithin the ocial class hours. Consult $ith your instructor for the s!eciBc schedule. 10. s the datasheet for a com!onent O un!versaQ] [es. Even if the manufacturers are diJerent the characteristics of a certain com!onent should be standardiFed. &or e=am!le the 2G"0, from e=as nstruments should have the same characteristics $ith the 2G"0, !roduced by *nalog Devices. 11. Can $e sit7in to other class schedules] [es. #rovided that there are e=tra stations'eui!ment. #lease refer bac to %ection 1.2 Laboratory Rules and Regulations. 12. +ur circuit is not $oring and date of !resentation is dra$ing near. :hat shall $e do] Do not be disheartened. uitters do not have a !lace here in EEE. [ou still need to !resent even if your !roect is not $oring. Io$ever you need to ustify and e=!lain the causes $hy your !roect is not $oring at the very least. nclude in your !resentation all the debugging tass you did to troubleshoot your circuit. t is better to !resent something than get a grade of 0U. +n the contrary do not be rela=ed. 1".Can $e !resent once $e are done] #lease refer to &* _. he instructor $ill not acce!t OambushQ !resentations. %tudents should at least reserve a schedule !rior to !roect !resentation. 1,.:e are !aying high laboratory fees in our tuition. :hy do $e e=!erience lac of com!onents in the nstruments Room] #rocuring materials in the government taes a long !rocess. he faculty and the admin are doing their best to address this situation. *lso EEE ", is not the only laboratory course in EEE. 15.*hmmm\] Chec the datasheet.
10 /
0eferences ;1<
%ource of article is unno$n. Edited version. Go co!yright infringement intended.
;2<
*nalog multimeter selector nob. mage ada!ted $$$.!ochefamily.org. Last accessed> Tanuary 2015.
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*nalog multimeter reading scale. mage ada!ted from htt!>''$$$.dreamstime.com'!hotos7images'analog7multimeter.html . Last accessed> Tanuary 2015.
;,<
Io$ to use a 3ultimeter. mage ada!ted from htt!>''$$$.$iiho$.com'4se7a73ultimeter. Last accessed> Tanuary 2015.
;5<
Resistors. mage ada!ted from htt!>''$$$.electronics7 tutorials.$s'resistor'resY2.html . Last accessed> Tanuary 2015.
;<
%tructure S circuit symbols for variable resistor'!ot. mage ada!ted from $$$.st7andre$s.ac.u. Last accessed> Tanuary 2015.
;/<
Ca!acitor images. mage ada!ted from $$$.$estXoridacom!onents.com. Last accessed> Tanuary 2015.
;)<
Ca!acitor value reading. mage ada!ted htt!>''$$$.electronics7tutorials.$s'ca!acitor'ca!Y1.html. accessed> Tanuary 2015.
;<
nductor images. mage ada!ted from htt!>''$$$.coil$s.com'. Last accessed> Tanuary 2015.
;10<
%ource of image is unno$n. Edited version. Go co!yright infringement intended.
;11<
Debugging circuits. *rticle Ble from htt!>''$$$7 inst.eecs.bereley.edu'qee,"'s!0"'labs'. Last accessed> Tanuary 2015.
from
from Last
;12<
#ID Comics 7 Debugging. mage ada!ted htt!>''$$$.!hdcomics.com'comics'archive.!h!]comicid/". accessed> Tanuary 2015.
from Last
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*ccur ccurac acy y and and #recisio ision. n. mage age ada ada!te !ted from $$$.e=t $$$.e=treme remetec tech.c h.com om.. Last accessed> Tanuary 2015.
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-oltage and Current %ources. mage ada!ted from htt!>''hy!er!hysi htt!>'' hy!er!hysics.!hy7 cs.!hy7 astr astr.gsu.edu' .gsu.edu'hbase'el hbase'electric'vi ectric'visource.html source.html.. Last accessed> Tanuary 2015.
;15<
(alvanometer. mage ada!ted from htt!>''en.$ii!ed htt!>'' en.$ii!edia.org'$i ia.org'$ii'(alva i'(alvanometer nometer.. Last Last access accessed> ed> Tanuar Tanuary y 2015.
=0b-&> LED anode and cathode. mage ada!ted from $$$.en $$$.eng.u g.utah tah.ed .edu u . Last accessed> Tanuary accessed> Tanuary 2015.
=0b-> &lash &lashin ing g LED LED cir circuit cuit.. mag mage e ada! ada!te ted d from from htt!>''$$$.5557timer7 circuits.com'Xashing7led.html . Last accessed> *ugust 2015.
=0b-)>
555 imer C #inouts. mage ada!ted from htt!>''$$$ htt!>'' $$$.instruct .instructables.co ables.com'id'&l m'id'&lashing7 ashing7LED7usin LED7using75557imer' g75557imer'.. Last accessed> Tanuary 2015.
=0b-4>
roubleshooting roubleshooting circuits. mage ada!ted from htt!>''$$$.allaboutcircuits.com'$orsheets'trouble1.html . accessed Last > Tanuary 2015. Diode. mage ada!ted from htt! htt!>'' >''en.a en.acade cademic. mic.ru ru.. Last accessed> Tanuary 2015.
=4-&>
10
Appendi% A< %am!le EEE #a!er for *, #age %iFe %iFe #lease see the follo$ing lins for the sam!le format. 1. H.doc htt!s>''$$$.dro!bo=.com's'd1ibaghl)f)t/m'EEEY#a!erY:ordYem!lateY*,Y -".do -". do c] c]dl dl0 0 2. H.!df
htt!s>''$$$.dro!bo=.com's'$!"a=0gghdcga'EEEY#a!erY:ordYem!late Y*,Y-".! df]dl0 *lso sharing here $ith !ermission a sam!le of #ost7Lab re!ort from EEE ", students ?*[ 1,7
15@\ ". H.!df htt!s>''$$$ htt!s>''$$$.dro!bo .dro!bo=.com's'a,Fhel",Fncteh'E=!t =.com's'a,Fhel",Fncteh'E=!tU200U20by U200U20by
U20uinuitoYTa U20uin uitoYTaland land oniY-alencia.!d oniY-alencia.!df]dl0 f]dl0 t is interesting to note here that this is their Brst #ost7Lab re!ort re!ort and yet they managed to !roduce a com!lete readable and coherent $or. t is not a !erfect re!ort of course but it is fairly great as a Brst re!ort. %tudents can use this as a model model or guide. guide. his should should >8" be co!ied for #ost7Lab 0. *t the end of the semester all students of EEE ", are e=!ected to !roduce re!orts $ith uality better than this one.
110
Appendi% D< %ome Gotes from ransducer ransducer Datasheets UEI Series >"C "hermistor &or the com!lete 4E %eries G GC C hermistor datasheet indly access the #D& at> htt!s>''$$$.dro!bo=.com's'ibfscvFlf$2'4EU20%eriesU20GC U20hermistor. !df]dl0
F!"ure B. &. yp!ca response curve te*perature versus res!stance o# UEI443 NC her*!stor .
111
Appendi% D< %ome Gotes from ransducer Datasheets LM3, Precision Centigrade "emperature Sensor &or a sam!le of com!lete L3"5 #recision Centigrade em!erature %ensor datasheet indly access the #D& at> htt!s>''$$$.dro!bo=.com's'/=/fb/n1f1vJ'L3"5U20Centigrade U20em!U20%e nsor.!df]dl0
F!"ure B. . Bas!c Cent!"rade te*perature sensor ?K2
K 150@.
Light !ependent 0esistor FL!0G &or a sam!le of com!lete Light De!endent Resistor ?LDR@ datasheet indly access the #D& at> htt!s>''$$$.dro!bo=.com's'yt1gcdrg!rv=de'LightU20De!endent U20Resistor.!df] dl0
F!"ure B. ).
112
Appendi% C< %ome Gotes from +!erational *m!liBer ?+!7*m!@ Datasheets LM14& 7eneral Purpose 8perational AmpliVer &or a sam!le of com!lete L3/,1 datasheet indly access the #D& at> htt!>''$$$.ti.com'lit'ds'symlin'lm/,1.!df
F!"ure C. &. LO34& operat!ona a*p!Rer p!n-outs.
L$3,3 igh5speed !ual 8perational AmpliVer &or a sam!le of com!lete L&"5" datasheet indly access the #D& at> htt!>''$$$.ti.com'lit'ds'symlin'lf"5"7n.!df
F!"ure C. . LF)) operat!ona a*p!Rer p!n-outs.
11"
Appendi% !< *vailable Com!onents in nstruments RoomH
he list above is a good reference to $hat com!onents are available in the nstruments Room. Io$ever EEE su!!orts various instructional laboratories
aside from EEE ",. he list availability or su!!ly might change $ithout !rior notice. HZindly tae note the version ?and hence revision date@ of this laboratory manual.
11,
Appendi% !< *vailable Com!onents in nstruments RoomH
HZindly tae note the version ?and hence revision date@ of this laboratory manual.
