To construct constr uct a full wave rectier and show that the Alternating Components are rectied into a direct current. Introduction : A full wave rectier is a device which is used to rectify rectify all the alternating current components in an alternating supply and mae it purely a direct current. The two alternating halves of an alternation alternation current current are rectied in a full wave rectier which is an advantage over a half wave rectier. rectier. !ost electronic devices cannot withstand very high voltage or alternating current current due to its intense high power. power. The use of "atteries in all devices is not practical as their t heir replacement replacement and dura"ility is a huge pro"lem as the device has to "e dismantled each time for such a replacement. replacement. #o these rectiers are used in most of the electronic devices lie T$%s& 'adios& Chargers& and (ights etc. There are several stages in a rectier. )ased on their rectication they are classied into two. The single staged * multi staged. +n the multi staged rectiers& more than two diodes are used and these are used in the a"ove,mentioned devices. The singled staged rectier has only 2 diodes& the one we are to discuss in this pro-ect. The multi diode rectier rectier has only 2 diodes& the one we are a re to discuss in this pro-ect. The multi diode rectiers rectiers has an eciency / 0.3 while that of the single is only 41.23 Theory involved The input transformer steps down the A.C mains from 256$ 7nominal8 to$ "etween the center tap and either of the two ends of the secondary winding. The transformer 5|Page
has a capa"ility of delivering a current current of 966 mA. The $ A.C. appearing across the secondary is the '!# v alue of the waveform and pea value would "e 1.1;4.volts. The diodes rectify rectify the A.C waveform appearing appearing across the secondary with the help of alternate forward and reverse "iasing. The capacitor further lters 003 of the resident components and this is left to pass through the resistance resistance and emerges out as irect Current Current and if used on an Alternating Current& Current& the ?uctuation will w ill "urn out the "ul". Materials required in the construction: Connecting wires& a plug& single lead wire , 2m& 5 = nuts * )olts of 2 to 5cm length& circuit "oard of mica& a small "o "o to place the model& a transformer& transformer& a capacitor& A 'esistor 71@8& P,B -unction diodes& +nsulation tape& )lades& soldering wa& soldering lead& soldering iron * sand paper. etails o! the materials used : i8 Connecting wires and a plug A normal insulated copper wire are are a"le to withstand 256 = 296 v is reDuired. reDuired. ii8 #ingle lead wire Thin wire with one single strand of copper well +nsulated and a"le to conduct a current current of 1 ampere or a >.C. current eciently. iii8 A circuit "oard A normal "oard of mica facilitated with clips to simplify the connection. iv8 Buts and "olt +n order to the "oard * transformer rmly. #iEe 2 = 5 cm. v8 #oldering wa * lead The wires are to "e soldered rmly to mae the connection tight so for this a thin lead
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wire is reDuired reDuired to a the connections and wa to mae the lead to hold on when soldered. vi8 A small "o To place the eDuipment safely. vii8 A "ul" To test the output voltage whether >irect or not.#pecication2.2 = v it will w ill get "urnt on application of A.C. viii8 A ,6, transformer Transformer +t is a device used to change the voltage of an alternating current. The transformer which converts low voltage to high voltage is called a step up transformer whereas the one which converts high voltage to low voltage is called a step down transformer. transformer. +t consists of alaminated core consisting of two coils& a primary * a secondary coil. +n a step up the t he num"er of turns in the secondary is greater than that of the primary and the reverse in a step down transformer. Fere we use a step down transformer which steps down 256$ to $ "etween the secondary terminals and the center tap. t ap. i8 A Capacitor The a"ility of a metal to store electric charges measures the capacitances of a conductor. conductor. +t provides high impedance to Alternating Current Current and stores them while all the >.C components are left to pass. There are are diGerent types of capacitors = a8 PA'A((H( PA'A((H( P(ATH CAPAC+TI' CAPAC+TI' "8 #PFH'+CA( CAPAC+TI' c8 CJ(+B>'+C(A( CAPAC+TI' CAPAC+TI' Fere we deal with a Cylindrical Capacitor.+t Capacitor.+t consistsof two coaialconducting cylindrical shells. >ue to attraction "etween unlie charges& the charges spread out uniformly and thus it gets charged. Capacitance is measured in it K Larads. Larads. The reactance a capacitors oGers to A.C. Current ; 1cMN where N is the freDuency of the supply. +t 9|Page
does not dissipate any power * the energy stored stored in it 2 eDual to O C$ . +n a capacitor $oltage $oltage does not change instantaneously. +t leads current *voltage "y an angle diGerent diGerent of 066. The capacitor can "e connected in 2 ways 18 +n #eries ;1MC;1MC 1<1MC2< * 28 +n Parallel ;7C ; C1 < C2 < C5 C 5 8 Fere we use capacitor of 1666 K L * 29 v. 8 A 'esistor A resistor is an electronic components whose resistance value tells us a"out the opposition it oGers to the ?ow of electric current. current. 'esistance is measured in ohms 78.Qe determine the value of a resistor using the color coding on the rings of the resistor = 1. )lac = 6 . Rreen, 9 2. )rown = 1 S. )lue, 5. 'ed = 2 4. $oilet,S . Irange = 5 0. Rrey,4 Rrey,4 9. Jellow = 16. Qhite,16 Tolerance Tolerance Rold , 93 #ilver , 163 Colorless , 263 !easurement 1st Color , 1stdigit 2nd Color , 2nd digit 5rd Color , Power to 16 th Color , Tolerance
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Lor H.g.: Lor a resistor of color code = "rown& "lac& green * gold. The resistance value is 16U16993.Fere we use a single resistor of )rown& 'ed& 'ed * Rold color rings. +t%s $alue ; 12U16 293.
'esistance can "e connected in 2 ways = +n series& ' ; 7'1 < '2 < '5 ..8
*
+n Parallel 1M';1M'1<1M'2< i8 P,B -unction >iodes Qhen one side of a semiconductor crystal 7Rermanium or silicon8 is doped with acceptor impurity atoms and the other side with w ith donor impurity atoms a PB -unction is formed. +t is also called a semiconductor or crystal diode. Qhen diGusion of the two regions occur a resultant potential "arrier " arrier is created "etween the two sides due to migration of electrons and holes. Qhen the diode is connected with P side to positive terminal of a "attery* B side to =ve terminal it is said to "e forward "iased * reverse reverse "iased when reversed. reversed. +n forward "iasing the applied positive potential repels the holes and turns a current current is made to t o ?ow overcoming the internal potential )arrier. Qhile in reverse "iasing the =ve electrons
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1st attract the holes and widen the t he )arrier and then only the repulsion "etween the inner electrons occur and current current ?ows. #o theoretically no current current ?ows through due to the widening w idening of the Potential "arrier "ut practically a very small current does ?ows through. >iGerent >iGerent types of diodes are present = 1. Vener diode 2. PB -unction diode 5. (H> . (A> 9. #olar cell Fere we use a P,B -unction diode. The grayish ring indicated the B side and the )lac color P side. ii8 Linally& Linally& small eDuipment such as a soldering so ldering iron to solder the lead& )lades& holders& insulation tapes = to insulate the wire from shocing and sand paper = to ru" the oidiEed wire ends are used. C+'CW+T >+AR'A!
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Connection details Connections are done as in the circuit. The A.C. supply is given to "oth the input wires of the transformer and the two ends of the secondary coil is given to the P side of the two diodes and the B side of the diodes are twined and then connected to one end of the capacitor and the other end to the center tap lead and to the resistor. resistor. Lurther& the other end of capacitor with the diode connect ion isconnected to the other end of the resistor. resistor. Connect 2 leads on "oth the ends of the resistor to measure the output and this is connected to the
1st when the A.C. is supplied to the transformer& it steps down the256$ main supply to volts. +t has a capa"ility of delivering a current of 966mA. The volts A.C. appearing across the secondary is the '!# value and the pea value is 4. volts. >uring the 1st half cycle of the A.C. input >iode >1 is forward "iased and a current current X+% ?ows in the t he circuit in the direction S1D1ABEOS1. >uring this time diode >2 is reverse "iased. #o it does not conduct any electric current. >uring the net half cycle the diode >2 is forward and >1 is reversed. Fence >2 conducts current in the direction S2D2ABEOS2 and >1 does not conduct any current. current. +n su"seDuent s u"seDuent half cycles of the A.C current the a"ove processes are repeated. repeated. +n "oth the half cycles it is clear that current current ?ows through the resistor in only one direction A)H. Hven though the voltage across '( is unidirectional it will still contain a few A.C components. This is ltered and made smooth using a capacitor& which lters 003 of the A.C current. current. A resistor is then used to ad-ust the t he output voltage. Qe Qe can then test the oMp $oltage using a multi,meter. Hciency of 'ectication , Y ; >.C power output Total A.C input power for a half wave rectier& Y / 6.6 ; 6. 3 for a full f ull wave rectier& the one used here is Y / 6.412 ; 41.2 3 )y the use of more num"er of diodes the eciency can "e increased to a maimum of 0.3. Fere we only use 2 diodes. The use of multiple capacitors also nearly lters all A.C components from the supply and resistance is ad-usted for the reDuired reDuired output. As this is a simple circuit& only one capacitor and a resistance is "eing used. )ut there will "e slight factor of A.C. current current still left in the output "ut it is negligi"le.
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I)#H'$AT+IB: Capacitance 7C8 7KL8 'esistance 7'8 7@ 8 11 | P a g e
