AUTOMATIC DRAINAGE CLEANING SYSTEM
In this project the proposed concept is to replace the manual work in drainage cleaning by automated system. Now-a-days even though automation plays a vital role in all industrial applications in the proper disposal of sewages from industries and commercials are still a challenging task. Drainage pipes are using for the disposal and unfortunately sometimes there may be loss of human life while cleaning the blockages in the drainage pipes. To overcome this problem and to save human life we implement a design “ Automatic Drain Cleaning System . we designed our project to use this in efficient way to control the disposal of wastages and with regular filtration of wastages! clearance of gaseous substance are treated separately and monitor the disposal in fre"uent manner. manner. INTRODUCTION
#uto #utoma mati ticc Drai Draina nage ge $ater ter clea cleani ning ng and and %ont %ontro roll &yst &ystem em 'sin 'singg auto auto mechanism proposed to overcome the real time problems. $ith the continued e(pansion of industries! the problem of sewage water must be urgently resolved due due to the the incr increa easi sing ng sewa sewage ge prob proble lems ms from from indu indust stri ries es of the the surr surrou ound ndin ingg environment. The waste and gases produced from the industries are very harmful to human beings and to the environment. )ur proposed system is to cleaning and control the drainage level using auto mechanism techni"ue. auto mechanism is the major controlling unit and the drainage level is monitor by municipal . In this system we used motor! chain! driver! bucket! frame.
WORING !RINCI!LE
The Device Is *lace #cross Drain &o That )nly $ater $ater +low Through ,ower rids. $aste ,ike ottle! /tc. +loating In Drain #re ,ifted y Teeth $hich Is %onnected To %hain. This %hain Is #ttached y ears Driven y 0otor. The /nergy *rovided To 0otor Is &olar *hotovoltaic %ell %onnected To It. $hen 0otor 1uns The %hain &tarts To %irculate 0aking Teeth To ,ift 'p. The $aste 0aterials #re ,ifted y Teeth #nd #re &tored In $aste &torage Tank
WORING !RINCI!LE
The Device Is *lace #cross Drain &o That )nly $ater $ater +low Through ,ower rids. $aste ,ike ottle! /tc. +loating In Drain #re ,ifted y Teeth $hich Is %onnected To %hain. This %hain Is #ttached y ears Driven y 0otor. The /nergy *rovided To 0otor Is &olar *hotovoltaic %ell %onnected To It. $hen 0otor 1uns The %hain &tarts To %irculate 0aking Teeth To ,ift 'p. The $aste 0aterials #re ,ifted y Teeth #nd #re &tored In $aste &torage Tank
Component Detail
Fundamentals Of Motor
Before we can exami amine the the func unction tion of a driv rive, we must understand understand the basic operation operation of the motor. motor. It is used to convert the electrical energy, supplied by the controller, to mechanical energy to move the load. There are really two types of motors, AC and DC. The basic principles are alie for both. !agnetism is the basi basis s for for all all elec electr tric ic moto motorr oper operat atio ion. n. It prod produc uces es the the for force re"uired to run the motor. There are two types of magnets the permanent magnet and the electro magnet. #lectro magnets have the advantage over permanent magnet in that the magnetic $eld can be made stronger. Also the polarity of the electro magnet can easi easily ly be reve reverse rsed. d. The cons constru truct ctio ion n of an elec electr tro o magn magnet et is simple. %hen a current passes through a coil of wire, a magnetic $eld is produced.
This magnetic $eld can be made stronger by winding the coil of wire on an iron core.
•
&ne end of the electro magnet is a north pole and the other end is a south pole The poles can be reversed by reversing the direction of the current in the coil of wire. 'iewise, if you pass a coil of wire through a magnetic $eld, a voltage will be induced into the coil And, if the coil is in a closed circuit, a current will (ow.
DC Motor •
%hen a curr urrent passes thr through a conductor, lines nes of magnetic
force
)(ux*
are
generated
around
the
conductor. The The di dirrecti ection on of the the (ux (ux is depe depend nden entt on the the direction of the current (ow. If you are thining in terms of conventional current (ow )positive to negative* then, using your right hand point your thumb in the direction of the current (ow and your $ngers will wrap around the conductor in the same direction of the (ux lines .
•
If you are thining in terms of electron current (ow )negative to positive* then you must use your left hand . If we loo at the air gap between two magnets that have their opposite poles facing each other, we would see magnetic lines of force )(ux* from the + to poles.
+ow, if we place a current carrying conductor in the air gap of two magnets, the lines of (ux in the air gap will be a-ected.
•
&n the side of the conductor where the lines of (ux oppose each other, the magnetic $eld will be made weaer . &n the side of the conductor where the lines of (ux are not opposing each
other,
the
magnetic
$eld
will
be
made
stronger.Because of the strong $eld on one side of the conductor and a wea $eld or, the other side, the conductor will be pushed into the weaer $eld .
•
+ow, lets apply this principle to the operation of the DC motor. The armature of the motor is a loop of wire )current carrying conductor*
which
is
free to
rotate.
The $eld
magnets are permanent or electro magnets with their + and poles facing each other to set up the lines of (ux in the air gap.
•
The armature is connected to the commutator which rides along the brushes which are connected to a DC power source. The current from the DC power source (ows from the positive lead, through the brush labeled A through one commutator section, through the armature coil, through the other commutator section, through the brush labeled A/ and bac to the negative lead.
Fundamentals of Motor - Part 2
This current will generate lines of (ux around the armature and a-ect the lines of (ux in the air gap . &n the side of the coil where the lines of (ux oppose each other, the magnetic $eld will be made weaer. &n the side of the coil where the lines of (ux are riot
opposing
each
other,
the
magnetic
$eld
is
made
stronger.Because of the strong $eld on one side of the coil and the wea $eld on the other side, the coil will be pushed into the weaer $eld and, because the armature coil is free to rotate, it will rotate.
The tor"ue available at the motor shaft )turing e-ort* is determined by the magnetic force )(ux* acting on the armature coil and the distance from the renter of rotation that force is. The (ux is determined by the current (owing through the armature coil and strength of the $eld magnets
The rotational speed )+* of the motor is determined by the voltage applied to the armature coil.
AC Motor The AC motor operates on the same principle of the &C motor )interaction between magnetic lines of (ux*. &ne ma0or di-erence is the &C motor re"uires DC current and the AC motor re"uires AC current. There
are
basically
two
motors1 synchronous and induction. The
types basic
principle
synchronous motors can be shown using two electro magnets and a permanent magnet.
of
AC for
%e can pass current through the coils in a direction so the north and south poles are aligned with the permanent magnet. The permanent magnet is free to rotate and is therefore called the rotor. The electro magnets are stationary and are therefore called the stator. Initially if the north and south poles are aligned in the motor and, because lie poles repel and unlie poles attract, the rotor will be pushed by the magnetic force of the lie poles. As it rotates, it will be pulled by the magnetic force of the unlie poles. &nce the rotor2s north and south poles line up with the stator2s south and north poles the stator current is reversed, thus changing the south and north pole orientation in the stator and the rotor is pushed again. This process repeats until the current in the stator stops alternating or stops (owing. In a three phase )34* motor, the stator (ux )magnetic force* does not 0ust alternate bac and forth but it actually rotates around the motor and the rotator actually follows this rotating magnetic $eld. This type of motor is called a synchronous motor because it always runs at synchronous speed )rotor and magnetic $eld of stator are rotating at exactly the same speed* . !aximum tor"ue is achieved when the stator (ux vector and the rotor (ux vector are 546 apart.
The induction motor operates much the same way that the synchronous motor does It uses the same magnetic principles to couple the stator and the rotor .7owever, one ma0or di-erence is the synchronous motor uses a permanent magnet rotor and the induction motor uses iron bars arranged to resemble a s"uirrel cage.
As the stator magnetic $eld rotates in the motor, the lines of (ux produced will cut the iron bars and induce a voltage in the rotor. This induced voltage will cause a current to (ow in the rotor and will generate a magnetic $eld. This magnetic $eld will interact with the stator magnetic $eld and will produce tor"ue to rotate the motor shaft8 which is connected to the rotor. The tor"ue available at the motor shaft is determined by the magnetic force )(ux* acting on the rotor and the distance from the center of rotation that force is. The (ux is determined by the current (owing through the stator windings.
Another
factor
determining
tor"ue
and
another
di-erence between the induction motor and the synchronous motor is slip. lip is the di-erence between the stator magnetic $eld speed and the rotor speed. As implied earlier, in order for a voltage to be induced into a conductor, there must be a relative
motion between the conductor and the magnetic lines of (ux. lip is the relative motion needed in the induction motor to induce a voltage into the rotor. If the induction motor ran at synchronous speed, there would be no relative motion and no tor"ue would be produced. This implies that the greater the slip, the greater the tor"ue. This is true to a limit. )9lease see speed:tor"ue curve below*
The above curve shows the speed:tor"ue characteristics that the typical induction motor would follow, excited by a given voltage and fre"uency. %e can see by this curve that the motor produces ;ero tor"ue at synchronous speed because there is no slip. As we apply a load, the rotor begins to slow down which creates slip. At about 4# slip )at the nee of the curve* we get maximum tor"ue and power transfer from the motor. This is really the best place on the curve to operate the motor.
The mathematical model allows the microprocessor to determine what the speed:tor"ue curve the motor will follow with any applied voltage and fre"uency, will be . This will allow the system to control the slip in the motor to eep it operating at the nee of the speed:tor"ue curve. This technology achieves extremely high performance. +ow that we have a basic understanding of the operation of the motor, we can better understand the function and operation of the high performance drive.
Planetary Gear Train (Epicyclic Gear Train 9lanetary gears solve the following problem. 'et=s say you want a gear ratio of >1 with the input turning in the same direction as the output. &ne way to create that ratio is with the following three?gear train1
Planetary Gear Train
In this train, the blue gear has six times the diameter of the yellow gear )giving a >1 ratio*. The si;e of the red gear is not important because it is 0ust there to reverse the direction of rotation so that the blue and yellow gears turn the same way. 7owever, imagine that you want the axis of the output gear to be the same as that of the input gear. A common place where this same?axis capability is needed is in an electric screwdriver. In that case, you can use a planetary gear system, as shown here1
Planetary Gear Train In this gear system, the yellow gear )the sun* engages all three red gears )the
planets * simultaneously. All three are attached to a plate )the planet carrier*, and they engage the inside of the blue gear )the rin!* instead of the outside. Because there are three red gears instead of one, this gear train is extremely rugged. The output shaft is attached to the blue ring gear, and the planet carrier is held stationary ?? this gives the same >1 gear ratio. Another interesting thing about planetary gear sets is that they can produce di-erent gear ratios depending on which gear you use as the input, which gear you use as the output, and which one you hold still. @or instance, if the input is the sun gear, and we hold the ring gear stationary and attach the output shaft to the planet carrier, we get a di-erent gear ratio. In this case, the planet carrier and planets orbit the sun gear, so instead of the sun gear having to spin six times for the planet carrier to mae it around once, it has to spin seven times.
"elocity ratio of Gear trains %e now that the #elocity ratio of a pair of gears is the inverse proportion of the diameters of their pitch circle, and the diameter of the pitch circle e"uals to the number of teeth divided by the diametral pitch. Also, we now that it is
necessary for the mating gears to have the same diametral pitch so that to satisfy the condition of correct meshing. Thus, we infer that the #elocity ratio of a pair of gears is the inverse ratio of their number of teeth. @or the ordinary gear trains we have )@ig a*
These e"uations can be combined to give the velocity ratio of the $rst gear in the train to the last gear1
7 N 5 N 4 N 2 6 7 N 3 N 5 N 4 6
=
7T 3T 5T 4 6 7T 5T 4T 2 6
=
N 2 N 3
=
T 3
=
n
T 2
PO$E% T%A&'M''O&
9ower transmission is the movement of energy from its place of generation to a location where it is applied to performing useful wor. 9ower transmission is normally accomplished by belts, ropes, chains, gears, couplings and friction clutches.
GEA% A toothed wheel that engages another toothed mechanism in order to change the speed or direction of transmitted motion.
A gear is a component within a transmission device that transmits rotational force to another gear or device. A gear is di-erent from a pulley in that a gear is a round wheel which has linages )teeth or cogs* that mesh with other gear teeth, allowing force to be fully transferred without slippage. Depending on their construction and arrangement, geared devices can transmit forces at di-erent speeds, tor"ues, or in a di-erent direction, from the power source. The most common situation is for a gear to mesh with another gear ear2s most important feature is that gears of une"ual si;es )diameters* can be combined to produce a mechanical advantage, so that the rotational speed and tor"ue of the second gear are di-erent from that of the $rst.
To overcome the problem of slippage as in belt drives, gears are used which produce positive drive with uniform angular velocity.
GEA% C)A''FCATO& ears or toothed wheels may be classi$ed as follows1
3. #ccording to the position of a(es of the shafts. The a(es of the two shafts between which the motion is to be transmitted! may be a. *arallel b. Intersecting c. Non-intersecting and Non-parallel
Gears for connectin! parallel s*afts "# S$ur Gear
Teeth is parallel to a(is of rotation can transmit power from one shaft to another
parallel shaft. &pur gears are the simplest and most common type of gear. Their general form is a cylinder or disk. The teeth project radially! and with these 8straightcut gears8.
&pur gears are gears in the same plane that move opposite of each other because they are meshed together. ear 9#: is called the 9driver: because this is turned by a motor. #s gear 9#: turns it meshes with gear 9: and it begins to turn as well. ear 9: is called the 9driven: gear.
%# A#&' Gear
icycle gearing is the aspect of bicycle drive train that determines the relation between the cadence! the rate at which the rider pedals! and the rate at which the drive wheel turns. )n some bicycles! there is only one gear and the gear ratio is fi(ed. 0any contemporary bicycles have multiple gears and thus multiple gear ratios. # shifting mechanism allows selection of the appropriate gear ratio for efficiency or comfort under the prevailing circumstances; for e(ample! it may be comfortable to use a high gear when cycling downhill! a medium gear when cycling on a flat road! and a low gear when cycling uphill. Different gear ratios and gear ranges are appropriate for different people and styles of cycling. # cyclist
internal planetary gears within the hub. +or a shaft-driven bicycle the gear ratio depends on the bevel gears used at each end of the shaft. +or a bicycle to travel at the same speed! using a lower gear 7larger mechanical advantage6 re"uires the rider to pedal at a faster cadence! but with less force. %onversely! a higher gear 7smaller mechanical advantage6 provides a higher speed for a given cadence! but re"uires the rider to e(ert greater force. Different cyclists may have different preferences for cadence and pedaling force. *rolonged e(ertion of too much force in too high a gear at too low a cadence can increase the chance of knee damage> cadence above 3?? rpm becomes less effective after short bursts! as during a sprint.
E+TE%&A) A&D &TE%&A) 'P,% GEA%
#xternal gear maes external contact, and the internal gear )right side pair* maes internal contact.
APP)CATO&' OF 'P,% GEA% #lectric screwdriver, dancing monster, oscillating sprinler, windup alarm cloc, washing machine and clothes dryer
2. Parallel elical Gear The teeth on helical gears are cut at an angle to the face of the gear. %hen two teeth on a helical gear system engage, the contact starts at one end of the tooth and gradually spreads as the gears rotate, until the two teeth are in full engagement.
This gradual engagement maes helical gears operate much more smoothly and "uietly than spur gears. @or this reason, helical gears are used in almost all car transmissions. Because of the angle of the teeth on helical gears, they create a thrust load on the gear when they mesh. Devices that use helical gears have bearings that can support this thrust load. &ne interesting thing about helical gears is that if the angles of the gear teeth are correct, they can be mounted on perpendicular shafts, ad0usting the rotation angle by 54 degrees.
C%O''ED E)CA) GEA%
(EARING
# bearing is a machine element that constrains relative motion between moving parts to only the desired motion. The design of the bearing may! for e(ample! provide for free linear movement of the moving part or for free rotation around a fi(ed a(is> or! it may prevent a motion by controlling the vectors of normal forces that bear on the moving parts. earings are classified broadly according to the type of operation! the motions allowed! or to the directions of the loads 7forces6 applied to the parts. The term 8bearing8 is derived from the verb 8to bear 8 a bearing being a machine element that allows one part to bear 7i.e.! to support6 another. The simplest bearings are bearing surfaces! cut or formed into a part! with varying degrees of control over the form! si=e! roughness and location of the surface. )ther bearings are separate devices installed into a machine or machine part. The most sophisticated bearings for the most demanding applications are very precise devices> their manufacture re"uires some of the highest standards of current technology.
+ig 35 S)uare Cou$ling
%#A#"*' C+AIN AND S!ROCET
$hen creating your own human powered vehicles! a chain drive will likely be your chosen power transfer system! as it is an ine(pensive! easy-to-install and highly efficient drive mechanism. icycle chains are fairly simple! re"uiring only one ine(pensive tool to remove and attach links. &ince a recumbent cycle will often re"uire a chain that is one and a half to 4 times the length of a regular upright bicycle chain! some basics should be known! as you will probably need to create the chain for your vehicle.
+ig 34 T,o -i..erent si/es o. 0icycle c1ain There are two basic types of bicycle chain; single speed chain and multi-speed chain. &ingle speed chain is mainly used on kids< bikes! 0@ bikes! coaster brake cruisers! and heavy cargo bikes. 0ulti-speed chain is used on standard speed bikes and mountain bikes that re"uire the use of a front and rear derailleur to change gears. oth types of bicycle chain have a pitch of 3A5 inch 7#N&I standard B2?6. This measurement indicates the length of the links. #lthough every type of bicycle chain and freewheel have a 3A5 in pitch! the width of chain varies "uite
a
bit!
from
4A458
to
3AC8.
&ingle speed bicycle chain is wider! having a width of 3AC inch. This type of chain will not fit a multi-speed freewheel nor will it fit properly through a derailleur cage. 0ulti-speed chain comes in various widths! with 4A458 being the most common si=e. 0ulti-speed chain is designed with a lot more side-to-side fle( to allow it to function properly with a derailleur system. +le(ibility is very important in a multi-speed system as the alignment of front and rear chain rings could be off by as much as 4 inches! depending on which gears are being used. +igure 3 shows the two common si=es of bicycle chain> 3AC8 on the top and 4A458 on the bottom. #t this angle! both chain types look very similar since you can only see the pitch! not the width.
+ig 32 Single s$ee- 2to$3 an- multi4s$ee- 20ottom3 +igure 5 gives you a much clearer view of the difference between a 3AC8 single speed chain 7top6 and a 4A458 multi-sped chain 7bottom6. The multi-speed chain is obviously narrower to fit the narrower chain rings on a multi-speed freewheel! and it also includes a beveled edge on the inner link to allow for better meshing with the teeth when switching gears. $hen bicycle building becomes your hobby! one of those 8must have8 tools will be a chain link tool as shown in +igure 4. +or under 5?! this small tool will give you a lifetime of service! able to break and rejoin any si=e of bicycle chain in a few seconds. The other method involves using a punch! a hammer! and a finishing nail! but I assure you! the chain link tool is so much easier and makes a worthwhile investment. To open a link! place the chain into the holder as shown in +igure 4! and then turn the vice handle clockwise to press out the link pin.
+ig 3E Remo5ing t1e lin6 $in +igure 2 shows the link pin pushed out by the chain link tool after turning the handle around a few times. This tool makes adjusting a chain pretty much effortless which is a good thing since you may have toadjust a long recumbent chain on a new project several times to get it right.
+ig 3F Se$arate- C1ain #fter breaking a chain with the link tool! it will look like the one shown in +igure E! with the link pin pressed through the roller to the outer plate. The pin only needs to be pressed far enough out so that the roller can be released. Notice that the pin has been slightly flattened at the end. This helps to ensure that it does not slip out of the plate hole! which is only holding it there by friction. I have broken many chains over the years! but it has always been a plate that has snapped! never a pin that has failed.
+ig 3G !arts o. a c1ain lin6 The two outer plates! pins! and rollers with inner plates are shown in +igure F. Normally! you would not need to pull a chain apart like this! as there are no wear parts that can be replaced. $hen a chain fails or stretches! the damage is always throughout the entire chain! which needs to be replaced. +or this reason! you should never join together chains that are from different manufacturers or may be years apart in wear. )ften! the outer plates will have the manufacturers: code stamped on them.
+ig 3C A sti.. lin6 causes $ro0lems #fter pressing a link back into a chain! the pin will have forced the plates together! causing a stiff link as shown in +igure G. This stiff link will cause a skip or jump every time it passes trough the rear derailleur! and must be fi(ed before use. # stiff link will always be created when first joining a chain! but it can easily be rela(ed.
+ig 3H Rela7ing a sti.. lin6 To fi( a stiff link! hold the chain so you can work the links side to side as shown in +igure C. *ress your thumbs against the plates on each side of the stiff link and force it back and forth until it no longer sticks when you bend the chain. )nce the link has been rela(ed! it will act like every other link without causing the problem shown in +igure G.
+ig 5? Multi4s$ee- .ree,1eel an- c1ain
+igure H shows a common F speed freewheel and the 4A458 chain that fits into it. #lthough the larger single speed 73AC86 chain will also fit into the teeth! it will be too wide to fit properly through the rear derailleur. ou could get away with the larger chain on a multi-sped freewheel if you plan to make your bike single speed 7fi(ed gear6.
+ig 53 C1ain an- a rear -erailleur The 4A458 multi-speed chain is not only designed to fit properly between the rear derailleur cage
as shown in +igure 3?! but it is also designed to fle( side-to-side! allowing some misalignment between opposing chain rings at the front and rear of a bicycle.
+ig 55 T1is c1ain is too t1in .or t1e teet1 0ulti-speed chain will not fit into the teeth of a single speed freehub or coaster hub as shown in +igure 33! so you don
+ig 54 Single s$ee- .ree,1eel an- c1ain The 3AC8 single speed chain is shown meshing with a 0@ freewheel in +igure 35. # coaster hub will have the same width of chain ring! re"uiring the 3AC8 wide chain.
+ig 52 Garage -oor o$ener c1ain &ometimes! you may re"uire a very long chain when making a long cargo trike or even a very tall bike. The chain shown in +igure 34 is standard 3AC8 single speed chain! but was taken from a discarded garage door opener! a good source for a very long length of single speed chain. $hen working on recumbent cycles and creative human powered vehicles! you will likely need to join together two or more bicycle chains! so consider purchasing an ine(pensive chain link tool! and be mindful of the different widths of bicycle chain. 1usty chain should always be discarded. )iling a chain is a matter of choice. I have never oiled a bicycle chain! and the current school of thought is that an oiled chain is less efficient and will wear out sooner due to trapping dirt between the links. 0aybe if your bike lives outdoors and is e(posed to alot of moisture! then a light brushing of light oil may be a good thing!
!OWER SU!!LY
In most of our electronic products or projects we need a power supply for converting mains #% voltage to a regulated D% voltage. +or making a power supply designing of each and every component is essential. Jere I:m going to discuss the designing of regulated EK *ower &upply. %omponent re"uired making E v power supplies are; 3. &tep down transformer 5. Koltage regulator
4. %apacitors 2. Diodes 8oltage regulator '
#s we re"uire a EK we need ,0GC?E Koltage 1egulator I%. GC?E I% 1ating ; •
Input voltage range GK- 4EK
•
%urrent rating Ic L 3#
•
)utput voltage range K0a(LE.5K !K0inL2.CK
LM7805 – Pin Diagram
!rinte- Circuit (oar-s 2!C(s3
The success of any creation is often dependent on the foundations it is built upon! be it the strength of a character! depth of a building:s foundations or the e(tent of a tree:s roots. 0uch in the same way! the success of any electronic device depends on what it is built on. The motherboard of any electronics device serves as a playground and a host to every form of electrical signal that performs some function for the e"uipment. e it the communication signal between the North ridge and processor on a computer! or a simple on-off signal in a routine school project! the effectiveness of the design is a function of the capabilities offered by the base board itself.
# !rinte- Circuit (oar- doesn:t just connect electrical components using etched copper pathways! but also provides mechanical strength to it. *rinted %ircuit oards! or more appropriately! *rinted $iring oards are found in almost all of the commercial products as a packaging medium as building blocks. !C(s are
a composite of organic andAor inorganic dielectric materials with many layers with wiring interconnects and also house components like inductors and capacitors. There isn:t any standard printing board as such and each board is uni"ue! often a function of the product itself. There are industry standards for almost every aspect of !C( -esign! controlled by I*%! for e(ample the I*%-5553! 9eneric &tandard on *rinted oard Design:. +istory
*%s have evolved from the electrical connection systems developed in the 3CE?s. The first patents on *rinted $ires were issued in 3H?4. #lbert Janson e(plained a layered structure of foil conductors laminated to insulation boards. #rthur erry patented a 9*rint-and-/tch: method in 3H34 and 0a( &choop patented +lame &praying metal onto a board via a mask. Thomas /dison had e(perimented with chemicals for plating conductors on linen paper way back in 3H?2! but the method of electroplating circuit patterns was finally successfully patented to %harles Durcase in the year 3H5G. %harles Ducas had earlier patented a techni"ue of creating electrical paths directly using stencils and electrically conductive ink in 3H5E. $orld $ar II saw the invention of circuit boards that could withstand gunshots. ut! the credit of developing the first *% is given to *aul /isler in 3H24! for developing a method of etching conductive circuits on copper foil bonded to a non-conductive base reinforced by glass. The method remained dormant until late E?s when the transistors were introduced for commercial use. The presence of wire leads on electronic components led to the development of 9Through Jole: technology where holes were drilled into the *% and the components soldered on to the board at those points. It was patented by a '.&. firm Ja=eltyne in 3HF3. Jowever! this process being slightly e(pensive and wasteful as the e(tra wire is cut off and not used much. Nowadays! 9surface mount: technology is gaining impetus as the demand for smaller! high density circuits is increasing. Ty$es o. !C(s
# *% can be of four types; rigid boards! fle(ible and rigid-fle( boards! metal-core boards and injection molded boards out of which the rigid board is the most popular. +urther these may be single sided! double sided or multilayered. The mechanical! electrical! chemical and thermal properties of the material should be considered while making *%s otherwise the reliability of
the board suffers. *resently! copper-clad laminates of different reinforced resin systems are used in rigid boards. /(amples include +ire resistant +1-2 epo(ies! *T+/! cyanate esters! ployimides etc. 0ost commonly used reinforcement material is continuous filament /-lass. +le(ible and rigid fle(-boards have random arrangements of conductors on a fle(ible base and may be withAwithout cover layers. Jere! the wiring is restricted to select areas of the plane. In case of constraining metal core technology! the *% can be of standard materials but the core materials must have low %oefficient of Thermal /(pansion and strength to constrain the *%. %opperInvar-%opper and %opper-0olybdenum-%opper are two popular materials for this purpose. 0olded boards have resins containing fillers which are molded into a die to form the re"uired shapes. efore anything is drawn onto the *%! it first has to be designed and verified by means of simulation. The design process is hierarchical in nature and may follow either one of the two approaches; 3. Top-Down Design. 5. ottom-'p Design To$4Do,n Design' Designers start with a higher abstraction layer and work on its general
functionality before creating a lower level building block for that layer. This creates organi=ed designs as the overall structure is drawn first and comple(ity is tackled at a later! lower stage. It is like manufacturing a car body first and then making custom parts for it.
(ottom4U$ Design' In this methodology! designers first develop the smallest block and then go
on to designing bigger blocks from smaller building blocks. This gives the design a modular approach and increases reusability of segments of design. This approach is like the manufacturing of a standard car in a factory! make the parts first and then put them into a single piece.
No matter what approach a designer chooses! the *% has to meet certain signal-integrity re"uirements like crosstalk! &&)! noise! delay and reflections! electromagnetic compatibility! /0I specifications and susceptibility re"uirements! thermal re"uirements! strength etc. Designing the *% is a part of a much wider design process. The netlist generation is an important step not just for *% designers but for circuit simulation too. Netlist contains a net! or a complete set of interconnections and components used. )nce the circuit simulation is successful! *% designers get down to working out the most simple and efficient circuit pattern or artwork. y placing the components on the board in the software! the si=e of the board may be known. There are various automated component placement software which can speed the work of the designer and have different algorithms working on their back end. Jowever! a seasoned designer would know that such software cannot always give satisfactory results and orderly placed components design is seldom the suitable design. The last step involves the placement of interconnect traces. This again can be an automated step using software based on popular algorithms like ,ee algorithm! Jightower router! pattern router! channel router and gridless routers! but designer discretion is re"uired. )nce this step is completed! the board:s integrity is verified by subjecting the trace pattern to Design 1ule %hecks which check if all the tracks! vias and pads have been placed according to the design rule sets or not. The length of interconnects can lead to severe signal distortions. Jence! &ignal-integrity! /0I compliance and other checks are performed as the ne(t step.
!C( Manu.acturing
#rtwork is generated by sending the design files in a particular format to plotters and transparencies for *% manufacturing are produced. #fter this the manufacturing of the *% commences. There are mainly five standard technologies used in *% manufacturing; 3. Mac1ining' This includes drilling! punching holes and routing on a *% with standard e(istent machinery and also new technologies like laser and water jet cutting. The strength of the board needs to be taken into account while machining for accurate hole diameters. &mall holes make this method costly and less reliable due to reduced aspect ratio and also making plating difficult. 5. Imaging' This step transfers the circuit artwork onto individual layers. &ingle sided or double sided *%s may use simple &creen *rinting technology for creating the patterns on a print-and-etch basis. ut this has a limitation on the minimum line width achievable. +or fine line boards and multilayer boards! *hotoimaging is used which may be applied by flood screen printing! dip coating! /lectrophoresis! roller laminating or li"uid roller coating. 1ecently! direct laser imaging and li"uid crystal light valve imaging have also been employed for the same. 4. Laminating' This process is mainly used for manufacturing multilayer boards! or the base laminates of singleAdouble sided boards. -stage epo(y resin impregnated glass sheets are pressed between layers using hydraulic press to bond the layers together. The pressing may be cold! hot! vacuum assisted or vacuum autoclave nominated offering close control on dielectrics and thickness. 2. !lating' It is basically the metalli=ation process which may be brought about either by wet chemical processes like electroless plating and electrolytic plating or dry processes like sputtering and %KD. $hile electroless plating offers high aspect ratios and no e(ternal current thus forming the core of additive technology! electrolytic plating is the preferred method for bulk metalli=ation. 1ecent developments like the plasma processing offer greater efficiency and "uality while ta(ing less on the environment. E. Etc1ing' The removal of unwanted metal and dielectric from the board takes place by either dry or wet processes. The uniformity of etching is the prime concern in this stage and to e(tend the fine line etching capabilities! new anisotropic etching solutions are being developed. Design 9lo,
The overall design flow can be summari=ed in the flowchart as shown below;
Throughout the manufacturing process of a *%! visual and electrical inspection is carried out to locate any flaws that might have crept in due to process automation like 9Tombstone effect: when the solder is heated too "uickly and one end of the component lifts up from the board failing to make contact! or e(cess flow of solder or bridging. /ven after the manufacturing process! the boards are tested for the output levels under varying conditions of environment! stress and strain. ack in the olden days! when *%s had just been introduced! military was the chief consumer. ut as the technology progressed and as the need grew! more and more interest was diverted towards better *%s and as of today! they serve as the base for a multitude of components! gadgets and devices ranging from ever innovating computers and cell phones to basic e"uipments like television! radio and toys for children. &oon there are going to be more mobile phones than there are people in this world and the trend will continue to rise. This might be a convenience to the users! but isn:t without ha=ards either! combating which offers great scope for people from diverse fields.
Ris6s : C1allenges
&older contains lead! which is a to(ic material. )n heating &older! lead fumes are formed which should not be inhaled. Jowever! it is necessary for performance reasons that such operations be done in closed areas. *roper processing and filtering of the fumes is re"uired before they are allowed to enter the earth:s atmosphere. Due to rapidly changing technology! devices become outdated and obsolete in a matter of few months and sometimes even weeks! and as progressive population goes on embracing newer technology! the pile of older devices continues to get bigger day by day. It would be disastrous for the ecosystem if poisonous substances entered the system through these discarded materials! hence it causes disposal problems. &everal mitigation procedures have been adopted by countries in order to tackle this situation like e-waste management! recycling electronic products! and salvaging parts from older e"uipment! reclaim and reuse of solder and buy back offers from the manufacturers. Development of cheap and nonto(ic ways to make electrical connections like water soluble conductive molded plastics are being developed to replace wires and solder. +urther! developments of technologies like threedimensional molded plastic boards assure us of *% technologies being a very dynamic field for many years to come.
Trans.ormer '
&electing a suitable transformer is of great importance. The current rating and the secondary voltage of the transformer is a crucial factor. •
•
•
The current rating of the transformer depends upon the current re"uired for the load to be driven. The input voltage to the GC?E I% should be at least 5K greater than the re"uired 5K output! therefore it re"uires an input voltage at least close to GK. &o I chose a F-?-F transformer with current rating E??m# 7&ince FM5 L C.2K6.
NOTE ;
#ny transformer which supplies secondary peak voltage up to 4EK can be used but as the voltage increases si=e of the transformer and power dissipation across regulator increases. Recti.ying circuit '
The best is using a full wave rectifier
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Its advantage is D% saturation is less as in both cycle diodes conduct.
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Jigher Transformer 'tili=ation +actor 7T'+6.
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3N2??G diodes are used as its is capable of withstanding a higher reverse voltage of 3???v whereas 3N2??3 is E?K
Center Tap Full Wave Rectiier
Koltage regulator is a device which provides fi( output voltage in spite of the variable input voltage supplied. It is a three terminal device. Koltage regulator basically comes in two different series; GC@@ and GH@@. Koltage regulator under GC@@ series are designed for positive inputs i.e. if while GH@@ series are designed for negative inputs. In market variety of voltage regulators are available with output as FK! HK! 35K! 3EK etc. Koltage regulator can also withstand over current drawn due to short circuit or overheating. It will cut off the circuit before damage occurs. )ne must take care while mounting the regulator because reverse polarity may destroy the regulator. *in configuration of negative and positive voltage regulator are shown in fig.
#s we know that output of regulator is fi(ed but with the help of voltage divider rule we can use EK regulator to deliver 35K. ut reverse is not possible that is we cannot obtain EK from 35K regulator. Jow we have calculated the value of resistor for different voltages&uppose value of resistor connected between com and output pin of regulator be 2G?ohm7136.This means we have 3?.Fm# current 7because K LEK and K L I16 available between pin! com and output. There would be some stand-by current of about 5.Em# which will be available between rotary switch and ground. Therefore total current available will be appro(. 34.3m#. Now! let:s say we want EK to 35K from this circuit. +or minimum EK! we will directly get this from regulator output. ut if you want ma(imum 35K! then apart from EK!additional GK would re"uire selection of appropriate resistor. Jere 1 LO K L GK I L34.3m# Therefore K LIM1 1 L E24ohm Therefore! we have to connect resistor of E24ohm with 2G?ohm to get the desire output of 35K. ut resistor of this value might not be easily available! so we can use resistor that has values near to it vi=. EF?ohm. Now if you want to obtain different voltage between EK and 35K use different values of resistor like if you want to obtain FK thenK LFK I L 3?.Fm# 1 L FKA3?.Fm# 1 L EFFohm
ut we have already connected resistor 13 of 2G?ohm so! for FK we have to use resistor value L3??ohm7 EFF- 2G?ohmL HF appro( 3??ohm6. &imilarly! you can calculate different values of resistor for obtaining different voltages. In this circuit we have used different resistors to obtain different values of voltage. ou can also use a variable resistor to obtain the different values of voltage with a single resistor.
IC E4F )
integrated circuit. It is a member of GC(( series of fi(ed linear voltage regulator I%s. The voltage source in a circuit may have fluctuations and would not give the fi(ed voltage output. The 5oltage regulator IC maintains the output voltage at a constant value. The (( in GC(( indicates the fi(ed output voltage it is designed to provide. GC?E provides PEK regulated power supply. %apacitors of suitable values can be connected at input and output pins depending upon the respective voltage levels. !in Diagram'
!in Descri$tion'
!in No
9unction
Name
3 5 4
Input voltage 7EK-3CK6 round 7?K6 1egulated output> EK 72.CK-E.5K6
Input round )utput
IC 54F
;>*= is a 5oltage regulator integrated circuit. It is a member of GH(( series of fi(ed linear
voltage regulator I%s. The voltage source in a circuit may have fluctuations and would not give the fi(ed voltage output. The voltage regulator I% maintains the output voltage at a constant value. The (( in GC(( indicates the fi(ed output voltage it is designed to provide. GH?E provides a regulated supply of -E K and 3# current. Its additional features include internal thermal overload protection! short circuit protection and output transistor safe operating area compensation. !in Diagram'
!in Descri$tion'
!in No
9unction
Name
3 5 4
round 7?K6 Input voltage 7EK-3CK6 1egulated output> EK 72.CK-E.5K6
round Input )utput
Ca$acitors '
Qnowledge of 1ipple factor is essential while designing the values of capacitors It is given by •
L3A724f1%6 7as the capacitor filter is used6
3. fL fre"uency of #% 7 E? J=6 5. 1Lresistance calculated 1L KAIc KL secondary voltage of transformer •
KLF5LC. 2
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1LC.2EAE??m#L3F.HR standard 3CR chosen
4. %L filtering capacitance $e have to determine this capacitance for filtering LKac-rmsAKdc Kac-rms L Kr A54 KdcL K0a(-7Kr A56 KrL K0a(- K0in •
Kr L E.5-2.C L?. 2K
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Kac-rms L .42F2K
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Kdc L EK
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L? .?FH5C
Jence the capacitor value is found out by substituting the ripple factor in L3A724f1%6 Thus! %L 5432 S+ and standard 55??S+ is chosen
Datasheet of GC?E prescribes to use a ?.?3+ capacitor at the output side to avoid transient changes in the voltages due to changes in load and a ?.44+ at the input side of regulator to avoid ripples if the filtering is far away from regulator. %ircuit Diagram
5! P"#er $uppl% Circuit u&ing 7805 !"ltage Regulat"r
