Basic Electronics Lab Manual c1t6h

INDEX S r. No .

Nam e o f t h e Ex pe rim e n t

1.

To ob s er ve s in e wa ve, s qu a re wa ve, t r ia n gu la r wa ve a n d ra m p wa vefor m s on t h e C.R.O. a n d to m ea s u r e a m p lit u d e a n d fr equ en cy of t h e wa vefor m s .

2.

To ob t a in V-I ch a r a ct er is t ics of PN ju n ction d iod e

3.

To ob t a in V-I ch a r a ct er is t ics of Zen er d iod e

4.

To ob t a in ch a ra cter is t ics of ligh t d ep en d a n t r es is tor (LDR)

5.

To b u ild a n d t es t p r a ct ica l cir cu it of LDR (Mea s u r e volta ge a t d ifferen t p oin t s )

6.

To ob t a in ch a ra cter is t ics of s em icon d u ctor p h ot o d iod e

7.

To ob s er ve wa veform a t t h e ou tp u t of h a lf wa ve r ect ifier with a n d wit h ou t filter ca p a cit or . To m ea s u r e DC volta ge, DC cu r r en t , r ip p le fa ct or wit h a n d with ou t filt er ca p a citor To ob s er ve wa veform a t t h e ou tp u t of fu ll wa ve r ect ifier with a n d wit h ou t filter ca p a cit or . To m ea s u r e DC volta ge, DC cu r r en t , r ip p le fa ct or wit h a n d with ou t filt er ca p a citor To ob s er ve wa vefor m a t t h e ou tp u t of b r id ge rect ifier wit h a n d with ou t filt er ca p a citor . To m ea s u re DC volt a ge, DC cu r ren t , r ip p le fa ct or wit h a n d wit h ou t filt er ca p a cit or

8.

9.

10.

To ob t a in ch a ra cter is t ics of ligh t em itt in g d iod e (LE D)

11.

To ob s er ve wa vefor m s a t t h e ou tp u t of cla m p er cir cu it s

12.

To ob s er ve wa vefor m s a t t h e ou tp u t of clip p er cir cu its

13.

To ob t a in com m on em it ter ch a r a cter is t ics of NPN t r a n s is tor

14.

To ob t a in com m on b a s e ch a ra cter is t ics of NPN t r a n s is t or

15.

To ob t a in com m on collect or ch a r a cter is t ics of NPN t r a n s is t or

16.

To u n d er s t a n d wor k in g of t r a n s is t or a s a s witch . To d r a w DC loa d lin e for given cir cu it. To ob s er ve in p u t -ou t p u t wa vefor m s of com m on em it ter (CE ) a m p lifier . To m ea s u re ga in of a m p lifier a t d ifferen t frequ en cies a n d p lot frequ en cy r es p on s e To ob s er ve in p u t -ou t p u t wa vefor m s of com m on collector (CC) a m p lifier . To m ea s u re ga in of a m p lifier a t d ifferen t frequ en cies a n d p lot frequ en cy r es p on s e To m ea s u re ga in of two s t a ge RC cou p led a m p lifier .

17.

18.

19.

Page No . 1

^/>dZKE/^>KZdKZzDEh>

20.

To ob t a in ch a ra cter is t ics of field effect tr a n s is t or (FE T)

21.

To m ea s u re ga in FET com m on s ou r ce (CS ) a m p lifier

To t es t in d ivid u a l cir cu it p r ep a red b y t h e s t u d en t (Get cir cu it fr om t h e fa cu lty, b u ild it , d r a w cir cu it d ia gr a m a n d tes t it in th e la b ora t or y. Wr ite t es t r es u lt s in th is p r a ct ica l) Instructions to the students: 22.

x

Draw circuit diagram of your practical in the given space as per circuit available in your laboratory

x

Write readings in the observation table

x

Draw waveforms in the given space

x

Simulate circuit using circuit simulator if hardware is not available in the lab

x

Every student must construct at least one circuit as per his choice or as given by the faculty

x

Write answers of the questions given in lab manual in worksheet section. Use text book, reference book or internet to find out answers of the questions

Suggest list of circuits that student will build individually x

DC power supply using IC 7805, 7812 or LM 317

x

Burglar alarm

x

Automatic street light switch

x

Siren using LM-555 timer

x

Automatic water tank overflow alarm

x

Automatic Emergency light

x

Sinusoidal waveform generator

x

RC coupled CE amplifier

x

IR (Infrared ) Switch

x

Overvoltage under-voltage protection switch

x

Simple intercom circuit

x

DTMF Encoder/decoder circuit

x

Telephone ring generator circuit

WZdDEd 'KsZEDEdE'/EZ/E'K>>' Z:

EXPERIMENT NO. 1 AIM: To ob s er ve s in e wa ve, s qu a re wa ve, t r ia n gu la r wa ve a n d r a m p wa vefor m s on t h e C.R.O. a n d t o m ea s u r e a m p lit u d e a n d fr equ en cy of th e wa vefor m s . In t ro du c t io n : C.R.O. (Ca t h od e Ra y Os cillos cop e) is t h e in s tr u m en t wh ich is u s ed to ob s er ve s ign a l wa vefor m s . S ign a ls a r e d is p la yed in t im e d om a in i.e. va r ia t ion in a m p lit u d e of t h e s ign a l wit h res p ect to t im e is p lot ted on t h e CRO s creen . X-a xis rep r es en t s tim e a n d Y-a xis rep r es en t s a m p lit u d e. It is u s ed to m ea s u re a m p lit u d e, fr equ en cy a n d p h a s e of th e wa vefor m s . It is a ls o u s ed t o ob s er ve s h a p e of th e wa vefor m . C.R.O. is u s efu l for t r ou b les h ootin g p u r p os e. It h elp s u s to fin d ou t ga in of a m p lifier , t es t os cilla t or circu it s . We ca n m ea s u re a m p lit u d e a n d fr equ en cy of t h e wa vefor m s a t t h e d iffer en t tes t p oin ts in ou r cir cu it . Th u s , it h elp s u s for fa u lt fin d in g p r oced u re. In d u a l ch a n n el C.R.O. X-Y m od e is a va ila b le wh ich is u s ed to cr ea te Lis s a jou s p a t ter n s La tes t d igita l s t or a ge os cillos cop e d is p la y volt a ge a n d frequ en cy d ir ect ly on th e LCD a n d d oes n ot r equ ire a n y ca lcu la t ion s . It ca n a ls o s t or e wa veform for fu r t h er a n a lys is . Mor e d eta iled s t u d y on C.R.O. will b e cover ed in E MI la b or a t or y (S E M-V). In th is p r a ct ica l, we will m ea s u r e a m p litu d e a n d fr equ en cy of t h e d ifferen t wa vefor m s lik e s in e wa ve, s qu a re wa ve, t r ia n gu la r wa ve a n d ra m p wa ve. Pro c e du re : 1 . Con n ect fu n ct ion gen er a t or ou tp u t a t th e in p u t of C.R.O. a t ch a n n el 1 or a t ch a n n el 2 2 . S elect p r op er ch a n n el i.e. if s ign a l is con n ected to ch a n n el 1 s elect CH1 a n d if s ign a l is con n ected t o ch a n n el 2 s elect CH2 3 . Ad ju s t Tim e / Div k n ob t o get s u fficien t t im e p er iod d is p la cem en t of th e wa ve on th e CRO s cr een . 4 . Wit h fin e t u n in g of tim e/ Div m a k e th e wa vefor m s tea d y on s creen . 5 . Us e tr igger in g con t rols if wa vefor m is n ot s t a b le 6 . Keep volt / d iv k n ob s u ch th a t wa vefor m is vis ib le on t h e s creen wit h ou t clip p in g 7 . Mea s u r e P-P rea d in g a lon g y-a xis . Th is r ea d in g m u lt ip lied with volt / d iv gives p ea k to p ea k a m p lit u d e of t h e a c i/ p wa ve. 8 . Mea s u r e h or izon ta l d ivis ion of on e com p lete cycle. Th is d ivis ion m u lt ip lied b y t im e/ d iv gives tim e p er iod of t h e i/ p wa ve. 9 . Ca lcu la te frequ en cy u s in g for m u la f = 1 / T. 1 0 . Note d own you r r ea d in gs in t h e ob s er va t ion ta b le ^/>dZKE/^>KZdKZzDEh>

1 1 . Dr a w wa vefor m s of s in e, s qu a re, r a m p a n d tr ia n gu la r in th e given s p a ce.

:: WORKS HEET :: Obs e rvat io n t able : Fun c t io n

Ve rt ic al Div is io n (a)

Vo lt / div (b)

Am plit u de (p-p) V=a*b

Ho riz o n t al Div (c )

Tim e / d iv (d)

S in e wa ve

S qu a re Wa ve

Tr ia n gu la r Wa ve

Ra m p Wa ve

Draw o bs e rve d wave fo rm s : S in e wa ve: (Am p litu d e : ________ Fr equ en cy: _____________ )


Tim e T =c *d

Fre q. F=1 / T

S qu a r e wa ve: (Am p litu d e : ________ Fr equ en cy: _____________ )

Tr ia n gu la r wa ve: (Am p litu d e : ________ Fr equ en cy: _____________ )

Ra m p : ((Am p lit u d e : ________ Fr equ en cy: _____________ )


Co n c lu s io n :

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ Qu e s t io n s : [1 ] Wh a t is t h e u s e of C.R.O. ?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ [2 ] Wh a t is th e h igh es t fr equ en cy t h a t ca n b e m ea s u r ed b y C.R.O. a va ila b le in you r la b ora tory?

_____________________________________________________________________ _____________________________________________________________________ [3 ] Wh a t is h igh es t volt a ge th a t ca n b e m ea s u red b y C.R.O. a va ila b le in you r la b or a t or y?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ [4 ] Wh a t you will d o t o m ea s u re volta ge wh ich is grea ter t h a n volt a ge lim it of t h e C.R.O.?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ [5 ] Wh y AC/ DC in p u t cou p lin g p u s h -b u t t on s wit ch is given ?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ [6 ] Wh a t d o you m ea n b y d u a l ch a n n el C.R.O.


_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ [7 ] Wh a t t yp e of d eflect ion m ech a n is m u s ed in C.R.O. to d eflect elect r on b ea m ?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ [8 ] How to t es t wh eth er C.R.O. p r ob e is in wor k in g con d it ion or n ot ?

_____________________________________________________________________ _____________________________________________________________________


EXPERIMENT NO. 2 AIM: To ob ta in V-I ch a ra cter is t ics of PN ju n ct ion d iod e In t ro du c t io n : Th e s em icon d u ctor d iod e is for m ed b y d op in g P-t yp e im p u r it y in on e s id e a n d N-t yp e of im p u rity in a n ot h er s id e of t h e s em icon d u ctor cr ys t a l for m in g a p -n ju n ct ion a s s h own in th e followin g figu r e. Ac c e p t o r io n s

J u nction

Do n o r io n s

Ho le s

Ele c t ro n s

p ty pe

-Wp

0

Wn

n t y pe

x

De p le t io n re g io n

At t h e ju n ction in it ia lly free ch a r ge ca r r ier s fr om b oth s id e r ecom b in e for m in g n ega t ively ch a r ged ion s in P s id e of ju n ction (a n a t om in P-s id e a ccep t elect r on a n d b ecom es n ega t ively ch a r ged ion ) a n d p os it ively ch a r ged ion on n s id e(a n a tom in n -s id e a ccep ts h ole i.e. d on a tes elect r on a n d b ecom es p os it ively ch a r ged ion )r egion . Th is r egion d ep lete of a n y t yp e of free ch a r ge ca r r ier is ca lled a s d ep let ion region . Fu r t h er r ecom b in a t ion of free ca r r ier on b ot h s id e is p r even ted b eca u s e of t h e d ep let ion volt a ge gen era ted d u e to ch a r ge ca r r ier s k ep t a t d is ta n ce b y d ep letion (a cts a s a s or t of in s u la t ion ) la yer a s s h own d ot t ed in t h e a b ove figu r e. Wo rk in g prin c iple : Wh en volta ge is n ot a p p lied a cr os s th e d iod e, d ep let ion r egion for m s a s s h own in t h e a b ove figu r e. Wh en t h e volt a ge is a p p lied b et ween th e t wo ter m in a ls of t h e d iod e (a n od e a n d ca t h od e) two p os s ib ilities a r is es d ep en d in g on p ola r it y of DC s u p p ly. [1 ] For wa r d -Bia s Con d it ion : Wh en th e +Ve ter m in a l of t h e b a t ter y is con n ected t o P-t yp e m a ter ia l & -Ve ter m in a l t o N-t yp e ter m in a l a s s h own in th e cir cu it d ia gr a m , th e d iod e is s a id to b e for wa r d b ia s ed . Th e a p p lica t ion of for wa r d b ia s volt a ge will for ce elect ron s in N-typ e a n d h oles in P-t yp e m a ter ia l t o recom b in e with t h e ion s n ea r b ou n d a r y a n d to flow cr os s in g ju n ction . Th is r ed u ces wid th of d ep let ion r egion . Th is fu r th er will r es u lt in in cr ea s e in m a jor ity ca r r ier s flow a cr os s th e ju n ct ion . If for wa r d b ia s is


fu r t h er in cr ea s ed in m a gn itu d e th e d ep let ion region wid th will con tin u e t o d ecrea s e, r es u lt in g in exp on en tia l r is e in cu r r en t a s s h own in id ea l d iod e ch a ra cter is tic cu r ve. [2 ]Rever s e-b ia s ed : If t h e n ega t ive ter m in a l of b a t ter y (DC p ower s u p p ly) is con n ected wit h P-typ e ter m in a l of d iod e a n d +Ve t erm in a l of b a t ter y con n ected to N typ e t h en d iod e is s a id t o b e r ever s e b ia s ed . In t h is con d it ion th e free ch a r ge ca r rier s (i.e. elect r on s in N-t yp e a n d h oles in P-t yp e) will m ove a wa y fr om ju n ct ion wid en in g d ep letion region wid th . Th e m in or it y ca r r ier s (i.e. –ve elect r on s in p -t yp e a n d +ve h oles in n -t yp e) ca n cr os s t h e d ep let ion region r es u lt in g in m in or it y ca r r ier cu r ren t flow ca lled a s r evers e s a t u ra t ion cu r ren t (Is ). As n o of m in or it y ca r r ier is ver y s m a ll s o t h e m a gn it u d e of Is is few m icr oa m p eres . Id ea lly cu r r en t in revers e b ia s is zer o. In s h or t , cu r r en t flows t h r ou gh d iod e in for wa r d b ia s a n d d oes n ot flow t h r ou gh d iod e in r ever s e b ia s . Diod e ca n p a s s cu r ren t on ly in on e d ir ect ion . Ex pe rim e n t Pro c e du re : x

x x x x x

Con n ect t h e p ower s u p p ly, volt m eter , cu r r en t m eter wit h th e d iod e a s s h own in t h e figu r e for for wa r d b ia s d iod e. You ca n u s e t wo m u lt im eter (on e t o m ea s u re cu r r en t th r ou gh d iod e a n d ot h er t o m ea s u re volta ge a cr os s d iod e) In cr ea s e volta ge fr om t h e p ower s u p p ly fr om 0 V to 2 0 V in s tep a s s h own in t h e ob s er va t ion ta b le Mea s u r e volta ge a cros s d iod e a n d cu r ren t t h r ou gh d iod e. Not e d own r ea d in gs in t h e ob s er va t ion ta b le. Rever s e DC p ower s u p p ly p ola r it y for rever s e b ia s Rep ea t th e a b ove p roced u re for t h e d iffer en t va lu es of s u p p ly volt a ge for r ever s e b ia s Dr a w VI ch a r a cter is tics for for wa r d b ia s a n d r ever s e b ia s in on e gr a p h

Circ u it diagram (fo rward bias ) +

A

-

1 K +

DC POWER S UPPY 0 -3 0 V

1 N4 0 0 7

V -


Circ u it diagram (re v e rs e bias ): -

A

+

1 K


1 N4 0 0 7

V +

:: WORKS HEET :: Obs e rvat io n t able : (Fo rward bias ) S r. No .

S u pply v o lt age (Vo lt )

1.

0

2.

0 .2

3.

0 .4

4.

0 .6

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0 .8

6.

1

7.

2

8.

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9.

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10.

8

11.

10

12.

15

13.

20

Dio de v o lt age (Vd)

Dio de c u rre n t (Id)


Obs e rvat io n t able : (Re ve rs e bias ) S r. No .

S u pply v o lt age

1.

0

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2

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5

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10

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15

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25

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Dr a w V-I ch a ra cter is tics of PN ju n ct ion d iod e:


Co n c lu s io n :

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ Qu e s t io n s : [1 ] Lis t im p or t a n t s p ecifica t ion s of th e d iod e

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ [2 ] Wh a t is b rea k d own volt a ge? Wh a t is t h e b r ea k d own volt a ge of d iod e 1 N4 0 0 1 a n d 1 N4 0 0 7 ?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ [3 ] Wh a t is t h e h igh es t for wa r d cu r r en t in th e d iod e 1 N4 0 0 7 a n d 1 N5 0 0 2 ?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ [4 ] Lis t d ifferen t t yp es of th e d iod e

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ [5 ] Lis t a p p lica t ion s of t h e d iod e?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ WZdDEd 'KsZEDEdE'/EZ/E'K>>' Z:

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ [6 ] How t o ch eck d iod e wit h h elp of m u lt im eter ?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ [7 ] Wh a t is th e r ea s on for r ever s e s a tu r a tion cu r r en t ? _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ [8 ] Wh a t is t h e for wa r d volta ge d r op of s ilicon d iod e a n d ger m a n iu m d iod e? _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ [9 ] Dr a w id ea l ch a ra cter is tics of d iod e.


EXPERIMENT NO. 3 AIM: To ob ta in V-I ch a ra cter is t ics of Zen er d iod e In t ro du c t io n : Th e Zen er d iod e is d es ign ed t o op er a te in r ever s e b r ea k d own r egion . Zen er d iod e is u s ed for volt a ge r egu la t ion p u r p os e. Zen er d iod es a re d es ign ed for s p ecific r ever s e b r ea k d own volta ge ca lled Zen er b r ea k d own volt a ge (VZ). Th e va lu e of VZ d ep en d s on a m ou n t of d op in g. Br ea k d own cu r r en t is lim it ed b y p ower d is s ip a t ion ca p a cit y of th e zen er d iod e. If p ower ca p a city of th e Zen er is 1 W a n d Zen er volta ge is 1 0 V, h igh es t rever s e cu r r en t is 0 .1 A or 1 0 0 m A. If cu r ren t in cr ea s es m or e t h a n th is lim it , d iod e will b e d a m a ged . For wa r d ch a ra cter is t ics of t h e Zen er d iod e is s im ila r t o n or m a l PN ju n ction d iod e. Ex pe rim e n t Pro c e du re : x Con n ect t h e p ower s u p p ly, volt m eter , cu r r en t m eter wit h th e d iod e a s s h own in t h e figu r e for r ever s e b ia s . You ca n u s e t wo m u lt im eter (on e to m ea s u r e cu r ren t th r ou gh d iod e a n d oth er to m ea s u re volta ge a cr os s d iod e) x In cr ea s e volta ge fr om t h e p ower s u p p ly fr om 0 V to 2 0 V in s tep a s s h own in t h e ob s er va t ion ta b le x Mea s u r e volta ge a cros s d iod e a n d cu r ren t t h r ou gh d iod e. Not e d own r ea d in gs in t h e ob s er va t ion ta b le. x Rever s e DC p ower s u p p ly p ola r it y for for wa r d b ia s x Rep ea t th e a b ove p roced u re for t h e d iffer en t va lu es of s u p p ly volt a ge for r ever s e b ia s x Dr a w VI ch a r a cter is tics for r ever s e b ia s a n d for wa r d b ia s in on e gr a p h Circ u it diagram (re v e rs e bias ) +

A

-

1 K +


Ze n e r Dio de


V -

Circ u it diagram (fo rward bias ): -

A

+

1 K


Ze n e r Dio de

V +

:: WORKS HEET :: Obs e rvat io n t able : (Re ve rs e bias ) S r. No .


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Dio de v o lt age (VZ)

Dio de c u rre n t (IZ)


Obs e rvat io n t able : (Fo rward bias ) S r. No .


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Draw V-I c h arac t e ris t ic s o f Ze n e r dio de :


Co n c lu s io n :

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ Qu e s t io n s : [1 ] Wh a t is th e b r ea k d own volta ge of Zen er d iod e u s ed in you r p r a ctica l? Wh a t is t h e p ower ca p a cit y. Wh a t is t h e m a xim u m cu r r en t t h a t you ca n p a s s th r ou gh it?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________

[2 ] Ca n we op er a te n or m a l PN ju n ct ion d iod e in b r ea k d own r egion for lon ger d u ra t ion ? Give rea s on

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ [3 ] Wh a t is t h e s p ecia lt y of Zen er d iod e s o a s we ca n op er a te it in b r ea k d own r egion for lon ger d u r a t ion

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ [4 ] Wh a t is t h e d ifferen ce b etween Zen er b rea k d own b r ea k d own ?

a n d Ava la n ch e

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ ^/>dZKE/^>KZdKZzDEh>

_____________________________________________________________________ _____________________________________________________________________ [5 ] Dr a w Zen er r egu la tor cir cu it to ob ta in r egu la ted DC volta ge 6 .8 V. Con s id er in g in p u t DC volt a ge in t h e r a n ge fr om 1 0 V t o 3 0 V. Con s id er loa d r es is ta n ce of 1 0 KŸ

[6 ] Deter m in e m a xim u m a n d m in im u m va lu e of Zen er cu r ren t if va lu e of s er ies res is ta n ce is 1 K, loa d res is ta n ce is 2 K a n d in p u t va r ies fr om 1 0 V t o 3 0 V. Zen er volt a ge is 5 V.

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ [7 ] Dr a w ou t p u t wa vefor m in t h e cir cu it of qu es t ion 5 , if we a p p ly AC wa ve of 1 0 V a t th e in p u t.

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________


EXPERIMENT NO. 4 AIM: To ob ta in ch a ra cter is t ics of ligh t d ep en d a n t res is t or (LDR) In t ro du c t io n : Ligh t d ep en d a n t res is t or is d evice in wh ich r es is ta n ce d ep en d s on in ten s it y of ligh t . Res is ta n ce of LDR d ecrea s es a s ligh t in t en s it y in cr ea s es . Typ ica l exa m p le of LDR is Ca d m iu m S u lfid e p h oto cell. Typ ica l r es is ta n ce for b r igh t ligh t is 2 0 0 Ÿ DQG IRU GDUN FRQGLWLRQ LW LV DURXQG 0Ÿ +RZHYHU WKHVH va lu es d ep en d s on s ize a n d m a ter ia l u s ed for t h e con s t r u ction of LDR. LDR ca n b e u s ed a s a ligh t s en s or . We ca n con s t r u ct a u tom a t ic s t reet ligh t con t r oller , b u r gla r a la r m , a u tom a t ic b r igh tn es s con t r oller for t elevis ion et c. a p p lica t ion s u s in g LDR. Pro c e du re : x x x x x

Con n ected t h e cir cu it a s p er in s tr u ction fr om th e fa cu lt y Con n ect t h e va r ia b le AC s u p p ly t o t h e la m p . S ee a s we ch a n ge AC s u p p ly, ligh t in t en s ity ch a n ges . Now a d ju s t th e la m p in s u ch a wa y t h a t its m a xim u m ligh t fa lls on LDR. Va r y AC s u p p ly wh ich will ch a n ge th e ligh t in ten s it y a n d recor d t h e r es is ta n ce va lu e in th e ob s er va tion ta b le Dr a w t h e AC Volta ge ver s u s cu r ren t flowin g t h r ou gh LDR & ca lcu la te th e d yn a m ic r es is ta n ce of LDR for ea ch s et t in g of AC volta ge.

:: WORKS HEET :: Circ u it diagram : (Dr a w cir cu it t h a t you h a ve u s ed d u r in g p r a ct ica l)


Obs e rvat io n t able : Res is ta n ce a t d a r k con d it ion : ________________________ Res is ta n ce a t n or m a l ligh t : ___________________________ S r n o.

AC Volt a ge (La m p in ten s ity )

Res is ta n ce of LDR

1 2 3 4 5 6 7 8 9 10 11

Co n c lu s io n :

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________


Draw graph o f In t e n s it y v ariat io n ve rs u s re s is t an c e

Qu e s t io n s : [1 ] Wh a t is u n it of Ligh t ? How you m ea s u r e Ligh t?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ [2 ] Wh a t d o you m ea n b y p h ot ocon d u ct ive cell?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ [3 ] Lis t a n y t wo p ra ctica l a p p lica t ion s of LDR.

_____________________________________________________________________ _____________________________________________________________________ ^/>dZKE/^>KZdKZzDEh>

EXPERIMENT NO. 5 AIM: To b u ild a n d t es t p ra ct ica l cir cu it of LDR (Mea s u re volta ge a t d ifferen t p oin ts ) Circ u it diagram : (Dr a w cir cu it d ia gr a m a va ila b le in you r la b or a t or y)

Obs e rvat io n s : Volt a ge on t h e ter m in a l of th e LDR wh en r ela y is OFF: V1 = _______________

V2 = _______________

Volt a ge on t h e ter m in a l of th e LDR wh en r ela y is ON: V1 = _______________

V2 = _______________

Ex plain c irc u it o pe rat io n in brie f:

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________


EXPERIMENT NO. 6 AIM: To ob ta in ch a ra cter is t ics of s em icon d u ct or p h oto d iod e In t ro du c t io n : Th e s em icon d u ct or p h ot od iod e is a ligh t d etect or d evice wh ich d etects p r es en ce of ligh t . It is u s ed t o con ver t op t ica l p ower in to elect r ica l cu r ren t . PN ju n ction Ph ot o d iod e h a ve P typ e a n d N t yp e s em icon d u ctor for m s ju n ction . Th in P typ e la yer is d ep os ited on N t yp e s u b s t r a te. P-N ju n ct ion h a s a s p a ce ch a r ge r egion a t th e in ter fa ce of th e P a n d N t yp e m a ter ia l. Ligh t en ter s th r ou gh P-la yer a s s h own in th e followin g figu r e. Th is d iod e h a s r ela t ively t h in d ep let ion r egion a r ou n d t h e ju n ction . It is r ever s e b ia s ed to in cr ea s e wid t h of t h e d ep let ion region . Ph ot on s of ligh t en ter in g in P-la yer ion ize elect r on -h ole p a ir . Ph oton gen era tes electr on -h ole p a ir in th e d ep let ion r egion t h a t m oves ra p id ly with t h e d r ift velocity b y th e electr ic field .

PHOTODIODE

Res p on s ivit y is im p or t a n t tech n ica l ter m r ela ted t o t h e p h otod iod e. It is r a t io of p h otocu r r en t t o in cid en t op tica l p ower . Res p on s ivity of t h e p h ot od iod e is p r op or t ion a l t o wid th of th e ju n ction . Ph oto d iod e is u s ed in fib er op t ic com m u n ica tion a t r eceiver s id e. It d etect s in com in g ligh t fr om t h e fib er en d a n d con ver t it in to elect r ica l s ign a l. It ca n b e a ls o u s ed in rem ote con t r ol r eceiver . Ex pe rim e n t Pro c e du re : x Con n ect t h e p ower s u p p ly, volt m eter , cu r r en t m eter wit h th e p h ot od iod e a s s h own in t h e figu re x Ap p ly 1 0 V fr om t h e DC p ower s u p p ly x In cr ea s e AC p ower given t o la m p t o in cr ea s e in ten s it y x Mea s u r e r ever s e lea k a ge cu r ren t (p h ot o cu r r en t ) of p h ot od iod e for d ifferen t ligh t in ten s it y x Dr a w gra p h of ligh t in t en s ity ver s u s p h otocu r r en t . ^/>dZKE/^>KZdKZzDEh>

Circ u it diagram : 1K

-

A

+

LAMP AC 230V

12V

PHOTODIODE

:: WORKS HEET :: Obs e rvat io n t able : S r n o.

AC Volt a ge (La m p in ten s ity )

Ph ot ocu r r en t

1 2 3 4 5 6 7 8 9 10 11


DC Vo lt a g e 1 0 V or 2 0 V

Draw graph o f Ligh t ve rs u s ph o t o c u rre n t :

Co n c lu s io n :

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ Qu e s t io n s : [1 ] Wh a t is t h e d ifferen ce b et ween LDR a n d p h ot od iod e? Wh a t t yp e of con ver s ion ta k es p la ce in p h ot od iod e?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ [2 ] Is p h ot ocu r ren t d ep en d s on wa velen gth of in cid en t ligh t?

_____________________________________________________________________ _____________________________________________________________________


EXPERIMENT NO. 7 AIM: To ob s er ve wa vefor m a t t h e ou tp u t of h a lf wa ve rect ifier with a n d wit h ou t filter ca p a citor . To m ea s u re DC volta ge, DC cu r r en t, r ip p le fa ct or wit h a n d wit h ou t filter ca p a cit or In t ro du c t io n : On e of t h e ver y im p or t a n t a p p lica tion s of d iod e is in DC p ower s u p p ly a s a r ectifier to con ver t AC in to DC. DC Power s u p p ly is th e im p or ta n t elem en t of a n y electr on ic equ ip m en t. Th is is b eca u s e it p rovid es p ower t o en er gize a ll elect r on ic cir cu its lik e os cilla t or s , a m p lifier s a n d s o on . In elect r on ic equ ip m en t s , D.C. p ower s u p p ly is m u s t . For exa m p le, we ca n ’t th in k of t elevis ion , com p u t er , ra d io, t elep h on e, m ob ile a s well a s m ea s u r in g in s tr u m en t s lik e CRO, m u lt i-m eter etc. wit h ou t DC p ower s u p p ly. Th e r elia b ility a n d p er form a n ce of th e elect r on ic s ys t em p r op er d es ign of p ower s u p p ly is n eces s a r y. Th e fir s t b lock of DC p ower s u p p ly is r ectifier . Rect ifier m a y b e d efin ed a s a n electr on ic d evice u s ed t o con ver t a c volt a ge or cu r ren t in to u n id ir ect ion a l volt a ge or cu r r en t. E s s en t ia lly rect ifier n eed s u n id ir ect ion a l d evice. Diod e h a s u n id ir ect ion a l p r op er ty h en ce s u ita b le for r ectifier . Rect ifier b roa d ly d ivid ed in to t wo ca tegor ies : Ha lf wa ve r ectifier a n d fu ll wa ve rectifier . In t h is exp er im en t , you will con s tr u ct h a lf wa ve rect ifier . Wo rk in g prin c iple o f h alf wave re c t ifie r: In h a lf wa ve rect ifier on ly h a lf cycle of a p p lied AC volta ge is u s ed . An ot h er h a lf cycle of AC volt a ge (n ega t ive cycle) is n ot u s ed . On ly on e d iod e is u s ed wh ich con d u ct s d u r in g p os it ive cycle. Th e cir cu it d ia gr a m of h a lf wa ve rectifier wit h ou t ca p a cit or is s h own in t h e followin g figu r e. Du r in g p os itive h a lf cycle of t h e in p u t volta ge a n od e of t h e d iod e is p os it ive com p a r ed wit h th e ca t h od e. Diod e is in for wa r d b ia s a n d cu r r en t p a s s es th r ou gh th e d iod e a n d p os itive cycle d evelop s a cr os s t h e loa d r es is ta n ce R L. Du r in g n ega t ive h a lf cycle of in p u t volt a ge, a n od e is n ega t ive wit h r es p ected to ca t h od e a n d d iod e is in rever s e b ia s . No cu r r en t p a s s es th r ou gh t h e d iod e h en ce ou t p u t volta ge is zer o.


Ha lf wa ve rectifier wit h ou t filter ca p a cit or con ver t AC volt a ge in to p u ls a t in g DC volta ge. Filter ca p a cit or is u s ed t o ob ta in s m ooth DC volt a ge. Con s tr u ct followin g cir cu it to p er for m t h is p r a ct ica l. Prac t ic al Circ u it diagram : 1 N4 0 0 7 + C 2 3 0 V AC i n pu t

12 V

1000u

A -

+ 10K

V -

Lis t of com p on en t s : [1 ] Tr a n s for m er In p u t : 2 3 0 V AC, ou t p u t : 1 2 V AC, 5 0 0 m A [2 ] Diod e 1 N4 0 0 7 [3 ] Res is tor 1 0 K

[4 ] Ca p a cit or 1 0 0 0 µF

[5 ] Toggle S wit ch

Con s tr u ct cir cu it on t h e gen er a l p u r p os e PCB. Keep t oggle s wit ch OFF t o p er for m p ra ct ica l of h a lf wa ve r ect ifier wit h ou t filter ca p a citor a n d ON to con n ect filter ca p a citor .

:: WORKS HEET :: Wav e fo rm s : [1 ] With ou t filt er ca p a cit or : In p u t Wa vefor m a t s econ d a r y of t ra n s for m er :

Ou tp u t wa vefor m :


[2 ] With filt er ca p a cit or : In p u t Wa vefor m a t s econ d a r y of t ra n s for m er :


Obs e rvat io n s : [1 ] With ou t filt er ca p a citor AC In p u t volta ge (r m s ) Vr m s = ___________ DC ou t p u t volt a ge VDC = ___________ DC cu r r en t:

IDC =______________

AC ou tp u t volt a ge (Rip p le volta ge) Vr : __________ Rip p le fa ctor : (Vr / VDC ) = ______________ [2 ] With filt er ca p a cit or AC In p u t volta ge (r m s ) Vr m s = ___________ DC ou t p u t volt a ge VDC = ___________ DC cu r r en t:

IDC =______________

AC ou tp u t volt a ge (Rip p le volta ge) Vr : __________ Rip p le fa ctor : (Vr / VDC ) = ______________


Co n c lu s io n :

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ Qu e s t io n s : [1 ] Defin e r ip p le fa ctor

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ [2 ] Wh a t is t h e effect of loa d res is ta n ce on r ip p le volta ge in p r es en ce of filter ca p a cit or ?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ [3 ] Wh a t is t h e effect of va lu e of filt er ca p a cit or on r ip p le volta ge?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________

[4 ] Wh a t is t h e PIV n eces s a r y for t h e d iod e if tr a n s for m er of 2 4 V is u s ed ?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ [4 ] Wh a t is th e m a t h em a tica l r ela t ion s h ip b et ween r m s in p u t AC volta ge a n d DC ou t p u t volta ge in h a lf wa ve rectifier with a n d wit h ou t filter ca p a cit or ?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ ^/>dZKE/^>KZdKZzDEh>

EXPERIMENT NO. 8 AIM: To ob s er ve wa vefor m a t th e ou t p u t of fu ll wa ve r ect ifier with a n d wit h ou t filter ca p a citor . To m ea s u re DC volta ge, DC cu r r en t, r ip p le fa ct or wit h a n d wit h ou t filter ca p a cit or In t ro du c t io n : Fu ll wa ve r ect ifier u t ilizes b oth th e cycle of in p u t AC volta ge. Two or fou r d iod es a re u s ed in fu ll wa ve rect ifier . If fu ll wa ve rectifier is d es ign ed u s in g fou r d iod es it is k n own a s fu ll wa ve b r id ge r ect ifier . Fu ll wa ve r ect ifier u s in g t wo d iod es wit h ou t ca p a cit or is s h own in t h e followin g figu r e. Cen ter ta p p ed t ra n s for m er is u s ed in t h is fu ll wa ve rect ifier . Du r in g th e p os it ive cycle d iod e D1 con d u ct s a n d it is a va ila b le a t th e ou t p u t . Du r in g n ega t ive cycle d iod e D1 r em a in s OFF b u t d iod e D2 is in for wa r d b ia s h en ce it con d u ct s a n d n ega t ive cycle is a va ila b le a s a p os itive cycle a t t h e ou t p u t a s s h own in t h e followin g figu r e. Note th a t d irect ion of cu r r en t in t h e loa d r es is ta n ce is s a m e d u r in g b oth th e cycles h en ce ou t p u t is on ly p os it ive cycles .

Adv an t age s o f fu ll wave re c t ifie r o ve r h alf wave re c t ifie r: x x x x

Th e r ect ifica t ion efficien cy is d ou b le th a n h a lf wa ve rectifier Rip p le fa ctor is les s a n d r ip p le frequ en cy is d ou b le h en ce ea s y t o filt er ou t . DC ou t p u t volt a ge a n d cu r r en t is h igh er h en ce ou t p u t p ower is h igh er . Bet ter tr a n s for m er u t iliza t ion fa ct or


x

Th er e is n o DC s a t u ra tion of core in t ra n s for m er b eca u s e t h e DC cu r r en t s in t wo h a lves of s econ d a r y flow in op p os it e d irect ion s .

Dis advan t age s : x x

Requ ires cen ter ta p t r a n s for m er Requ ires t wo d iod es com p a red t o on e d iod e in h a lf wa ve rectifier .

Prac t ic al Circ u it diagram : 1 N4 0 0 7 + C 2 3 0 V AC i n pu t 1 2 -0 -1 2 Vr m s

1000u

A -

+ 10K

V -

1 N4 0 0 7

Lis t of com p on en t s : [1 ] Tr a n s for m er (cen t er ta p p ed ) 1 2 -0 -1 2 V AC, 5 0 0 m A [2 ] Diod e 1 N4 0 0 7 ---- 2 No. [4 ] Ca p a cit or 1 0 0 0 µF

[3 ] Res is t or 1 0 K


Con s tr u ct cir cu it on t h e gen er a l p u r p os e PCB. Keep t oggle s wit ch OFF t o p er for m p r a ct ica l of fu ll wa ve r ect ifier wit h ou t filt er ca p a cit or a n d ON to con n ect filter ca p a citor .

:: WORKS HEET :: Wav e fo rm s : [1 ] With ou t filt er ca p a citor : In p u t Wa vefor m a t s econ d a r y of t ra n s for m er :






IDC =______________



[2 ] With filt er ca p a cit or AC In p u t volta ge (r m s ) Vr m s = ___________ DC ou t p u t volt a ge VDC = ___________ DC cu r r en t:

IDC =______________

AC ou tp u t volt a ge (Rip p le volta ge) Vr : __________ Rip p le fa ctor : (Vr / VDC ) = ______________ Co n c lu s io n :

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ Qu e s t io n s : [1 ] Wh a t is t h e fr equ en cy of AC com p on en t a t t h e ou t p u t of fu ll wa ve r ect ifier ? Give rea s on .

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ [2 ] Wh a t is t h e d iffer en ce in DC ou t p u t volt a ge in h a lf wa ve a n d fu ll wa ve r ect ifier for th e s a m e AC in p u t ?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ [3 ] Wh a t is t h e PIV n eces s a r y for t h e d iod e if t ra n s for m er of 2 4 -0 -2 4 V is u s ed ?

_____________________________________________________________________ _____________________________________________________________________ [4 ] Wh a t is th e m a t h em a tica l r ela t ion s h ip b et ween r m s in p u t AC volta ge a n d DC ou t p u t volta ge in h a lf wa ve rectifier with a n d wit h ou t filter ca p a cit or ?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ ^/>dZKE/^>KZdKZzDEh>

EXPERIMENT NO. 9 AIM: To ob s er ve wa vefor m a t th e ou tp u t of b r id ge r ect ifier wit h a n d with ou t filt er ca p a citor . To m ea s u re DC volta ge, DC cu r r en t , r ip p le fa ct or wit h a n d wit h ou t filter ca p a citor In t ro du c t io n : Th e Br id ge r ect ifier is a cir cu it , wh ich con ver ts a n a c volta ge t o d c volta ge u s in g b ot h h a lf cycles of th e in p u t a c volt a ge. Th e Br id ge r ect ifier cir cu it is s h own in t h e followin g figu r e.

Th e cir cu it h a s fou r d iod es con n ected to for m a b r id ge. Th e a c in p u t volt a ge is a p p lied to th e d ia gon a lly op p os it e en d s of t h e b r id ge. Th e loa d r es is ta n ce is con n ected b etween th e ot h er t wo en d s of t h e b r id ge. For t h e p os itive h a lf cycle of t h e in p u t a c volta ge, d iod es D1 a n d D2 con d u ct, wh erea s d iod es D3 a n d D4 rem a in in th e OFF s ta te. Th e con d u ct in g d iod es will b e in s er ies wit h t h e loa d r es is ta n ce R L a n d h en ce t h e loa d cu r r en t flows th r ou gh R L. For t h e n ega t ive h a lf cycle of t h e in p u t a c volta ge, d iod es D3 a n d D4 con d u ct wh er ea s , D1 a n d D2 rem a in OFF. Th e con d u ctin g d iod es D3 a n d D4 will b e in s er ies wit h th e loa d res is t a n ce R L a n d h en ce t h e cu r ren t flows t h r ou gh R L in th e s a m e d irect ion a s in t h e p reviou s h a lf cycle. Th u s a b i-d ir ect ion a l wa ve is con ver ted in t o a u n id ir ect ion a l wa ve.


Th e cir cu it d ia gr a m of t h e b r id ge r ect ifier wit h filt er ca p a cit or is s h own in t h e followin g figu r e. Wh en ca p a cit or ch a r ges d u r in g th e fir s t cycle, s u rge cu r r en t flows b eca u s e in itia lly ca p a citor a ct s lik e a s h or t cir cu it . Th u s , s u r ge cu r r en t is ver y la r ge. If s u r ge cu r r en t exceed s ra ted cu r r en t ca p a cit y of th e d iod e it ca n d a m a ge t h e d iod e. To lim it s u r ge cu r r en t s u rge res is ta n ce is u s ed in s er ies a s s h own in t h e figu r e. S im ila r s u r ge r es is ta n ce ca n b e u s ed in h a lf wa ve a s well a s cen ter -ta p p ed fu ll wa ve rectifier a ls o.

Br id ge r ect ifier p a ck a ge (com b in a t ion of fou r d iod es in for m of b r id ge) is ea s ily a va ila b le in th e m a r k et for va r iou s cu r r en t ca p a cit ies r a n gin g fr om 5 0 0 m A t o 3 0 A. For la b ora tor y p u r p os e you ca n u s e 1 A p a ck a ge. Adv an t age s o f bridge re c t ifie r: x

x x x

No cen ter ta p is r equ ir ed in t h e t ra n s for m er s econ d a r y h en ce tr a n s for m er d es ign is s im p le. If s tep p in g u p a n d s tep p in g d own n ot r equ ir ed t h a n t ra n s for m er ca n b e elim in a ted . (In S MPS u s ed in TV a n d com p u ter , 2 3 0 V is d ir ect ly a p p lied to t h e in p u t of b r id ge rectifier ). Th e PIV of th e d iod e is h a lf t h a n in cen ter t a p fu ll wa ve r ect ifier Tr a n s for m er u t iliza t ion fa ct or is h igh er th a n in cen ter ta p p ed fu ll wa ve r ectifier S m a ller s ize t ra n s for m er requ ir ed for given ca p a cit y b eca u s e tr a n s for m er is u t ilized effect ively d u r in g b oth AC cycles .

Dis advan t age s o f bridge re c t ifie r: x x x

Requ ires Fou r d iod es (Bu t p a ck a ge is low cos t ) For wa r d volta ge d r op a cr os s two d iod es . Th is will r ed u ce efficien cy p a r ticu la r ly wh en low volt a ge (les s t h a n 5 V ) is r equ ired . Loa d r es is ta n ce a n d s u p p ly s ou r ce h a ve n o com m on p oin t wh ich m a y b e ea r t h ed .


Prac t ic al c irc u it diagram : D1 D3 +

C 2 3 0 V AC i n pu t

V

+ D2

A

DC Ou t pu t

-

D4

Lis t of com p on en t s : [1 ] Tr a n s for m er 1 2 V AC, 5 0 0 m A [2 ] Diod e 1 N4 0 0 7 ---- 4 No. or 1 A b r id ge r ect ifier p a ck a ge [3 ] Res is tor 1 0 K

[4 ] Ca p a cit or 1 0 0 0 µF


Con s tr u ct cir cu it on t h e gen er a l p u r p os e PCB. Keep t oggle s wit ch OFF t o p er for m p r a ct ica l of fu ll wa ve r ect ifier wit h ou t filt er ca p a cit or a n d ON to con n ect filter ca p a citor .

:: WORKS HEET :: Wav e fo rm s : [1 ] With ou t filt er ca p a citor : In p u t Wa vefor m a t s econ d a r y of t ra n s for m er :






IDC =______________


[2 ] With filt er ca p a cit or AC In p u t volta ge (r m s ) Vr m s = ___________ DC ou t p u t volt a ge VDC = ___________ DC cu r r en t:

IDC =______________



Co n c lu s io n :

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ Qu e s t io n s : [1 ] Wh a t is t h e m a th em a t ica l exp res s ion for r ip p le fa ct or . Wh a t is t h e r ip p le fa ct or of b r id ge rect ifier wit h ou t filter ca p a cit or ?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ [2 ] Wh a t is th e m a th em a tica l r ela t ion s h ip b et ween r m s AC in p u t a n d DC ou tp u t fr om t h e b r id ge r ect ifier wit h a n d with ou t filter ca p a cit or ? If t r a n s for m er of 2 4 V is u s ed , wh a t is t h e DC ou t p u t volt a ge wit h a n d wit h ou t filt er ca p a cit or ?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ [3 ] Wh a t is t h e PIV n eces s a r y for t h e d iod e if t ra n s for m er of 1 2 -0 -1 2 V is u s ed ?

_____________________________________________________________________ _____________________________________________________________________ [4 ] Wh a t is t h e efficien cy of fu ll wa ve b r id ge r ectifier ?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________


EXPERIMENT NO. 1 0 AIM: To ob ta in ch a ra cter is t ics of ligh t em it t in g d iod e (LE D) In t ro du c t io n : LE D is s em icon d u ct or ju n ct ion d iod e wh ich em it s ligh t wh en cu r ren t p a s s es t h r ou gh it in for wa r d b ia s con d it ion . P typ e of s em icon d u ctor con s is t s of la r ge n u m b er of h oles wh ile N t yp e of s em icon d u ct or con s is t s of la r ge n u m b er of elect r on s . At zer o b ia s (n o volt a ge a cr os s ju n ct ion ), d ep let ion region exis t s a n d it s ep a r a te ou t t wo r egion s . Wh en LE D is for wa r d b ia s ed , b a r r ier p oten t ia l red u ces a n d d ep let ion region b ecom es n a r r ow. E lect r on cr os s es t h e d ep let ion r egion a n d r ecom b in es with h oles . S im ila r ly h oles cr os s es d ep letion r egion a n d r ecom b in e wit h electr on s . Ea ch r ecom b in a tion of h ole a n d elect r on p r od u ces p h ot on (ligh t ) Th e in t en s it y of ligh t em it ted d ep en d s on th e n u m b er of m in or ity ca r r ier s a va ila b le for r ecom b in a tion . Wa velen gt h (or fr equ en cy) of em it ted ligh t d ep en d s on b a n d ga p en er gy. Th e ligh t em it tin g d iod e wor k s b y th e p r oces s of s p on ta n eou s em is s ion . Ligh t s ou r ce m a ter ia l m u s t h a ve d ir ect b a n d ga p . In a d irect b a n d ga p s em icon d u ct or m a ter ia l elect r on a n d h ole r ecom b in e d irect ly a cr os s b a n d ga p with ou t n eed of th ir d p a r ticle to con s er ve m om en tu m . Ligh t s ou r ce m a ter ia ls a r e m a d e fr om com p ou n d of gr ou p -III (Al,Ga ,In ) a n d gr ou p -V (P,As ,S b ) elem en t .Th e wa velen gt h gen er a ted b y th e LE D d ep en d s on b a n d ga p en er gy a n d b a n d ga p en er gy d ep en d s on d op in g level of a b ove elem en t s . Let u s u n d er s ta n d rela t ion b et ween frequ en cy of em is s ion a n d en er gy. Ph ot on en er gy is rela ted to t h e em it ted fr equ en cy b y th e LED. Ph ot on en ergy E

(b eca u s e f

c O

hf

hc O

Velocity of light ) wavelength

Wh ere h = Pla n k ’s con s t a n t = 6 .6 2 5 ×1 0 -3 4 J -S c = Velocit y of th e ligh t = 3 ×1 0 8 m / s O = Wa velen gt h of em it t ed ligh t


Ex pe rim e n t Pro c e du re : x x x

x x x

Con n ect t h e p ower s u p p ly, volt m eter , cu r r en t m eter wit h th e LE D a s s h own in t h e cir cu it d ia gra m . In cr ea s e volta ge fr om t h e p ower s u p p ly fr om 0 V to 2 0 V in s tep a s s h own in t h e ob s er va t ion ta b le Mea s u r e volta ge a cros s LE D a n d cu r ren t t h r ou gh th e LE D. Not e d own r ea d in gs in t h e ob s er va t ion ta b le a n d a ls o ob s er ves ligh t com in g fr om LE D. Rever s e DC p ower s u p p ly p ola r it y for rever s e b ia s Rep ea t th e a b ove p roced u re for t h e d iffer en t va lu es of s u p p ly volt a ge for r ever s e b ia s Dr a w VI ch a r a cter is tics for for wa r d b ia s a n d r ever s e b ia s in on e gr a p h

Circ u it diagram (fo rward bias ) +

-

A

1 K +


LED

V -

Circ u it diagram (re v e rs e bias ): -

A

+

1 K


LED

V +


:: WORKS HEET :: Obs e rvat io n t able : (Fo rward bias ) S r. No .


1.

0

2.

0 .5

3.

1

4.

2

5.

5

6.

10

7.

15

8.

20



Obs e rvat io n t able : (Re ve rs e bias ) S r. No .

S u pply v o lt age

1.

0

2.

2

3.

5

4.

10

5.

15

6.

20




Dr a w V-I ch a ra cter is tics of t h e LE D:

Co n c lu s io n :

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ Qu e s t io n s : [1 ] Wh a t a r e th e a p p lica t ion s of LE D?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ [2 ] On wh ich fa ctor s color em itted fr om th e LE D d ep en d s ?

_____________________________________________________________________ _____________________________________________________________________ [3 ] Give t yp ica l va lu es of LE D volt a ge a n d cu r r en t?

_____________________________________________________________________ _____________________________________________________________________


EXPERIMENT NO. 1 1 AIM: To ob s er ve wa vefor m s a t t h e ou t p u t of cla m p er cir cu its In t ro du c t io n : Diod es a re wid ely u s ed in clip p in g a n d cla m p in g cir cu it s . Cla m p in g cir cu its a re u s ed t o ch a n ge DC level (a vera ge level) of t h e s ign a l wh ich a d d s or s u b tr a ct s DC va lu e wit h t h e s ign a l. In cla m p in g, s h a p e of wa vefor m rem a in s s a m e on ly offs et va lu e (DC level) will ch a n ge. Pos it ive cla m p in g a d d s p os it ive DC level in t h e s ign a l wh ile n ega t ive cla m p in g a d d s n ega t ive DC level in t h e s ign a l. Ca p a cit or is wid ely u s ed in t h e cla m p in g cir cu it. Typ ica l cla m p in g wa vefor m s for t h e s in u s oid a l s ign a l is s h own b elow for p os it ive cla m p in g a n d n ega tive cla m p in g.

Cla m p in g cir cu it is u s ed in vid eo a m p lifier of televis ion r eceiver to res t ore DC level of vid eo s ign a l t o p r es er ve overa ll b r igh tn es s of th e s cen e. Cla m p in g cir cu it is a ls o u s ed in offs et con tr ol of fu n ct ion gen era tor . Zer o offs et m ea n s n o DC va lu e is a d d ed in t h e AC s ign a l. Circ u it o pe rat io n : Typ ica l cir cu it op era tion of t h e p os it ive cla m p in g a n d n ega t ive cla m p in g is given b elow. ^/>dZKE/^>KZdKZzDEh>

Po s it ive c lam pin g:

Con s id er t h a t 4 V p ea k to p ea k s ign a l wit h zer o offs et is a p p lied a t t h e in p u t of th e cla m p in g cir cu it. On t h e fir s t n ega t ive h a lf cycle of th e in p u t s ign a l, d iod e D t u r n s ON b eca u s e a n od e volta ge is gr ea ter t h a n ca th od e volta ge. Ca p a cit or ch a r ges t o t h e n ega tive p ea k volta ge let u s s a y -2 V in ou r exa m p le. Th e va lu e of R s h ou ld b e h igh s o t h a t it will n ot d is ch a r ge t h e ca p a cita n ce. After com p let ion of n ega t ive cycle, p os it ive cycle s ta r t s a n d d iod e t u r n s OFF. Ca p a cita n ce volta ge is in s er ies wit h t h e in p u t volt a ge. As p er t h e Kir ch off’s la w ou t p u t volt a ge will b e a d d ition of in p u t volt a ge a n d ca p a cita n ce volta ge. In p u t s ign a l is p os it ive s win g of +2 V a n d ca p a cit or volt a ge is +2 V. Th u s d u r in g th e p os itive p ea k of t h e in p u t volt a ge t ot a l ou t p u t volta ge will b e +4 V. We ca n con s id er t h a t d u r in g t h e p os it ive cycle ca p a citor a ct s lik e a b a tter y a n d a d d s +2 V in th e in p u t . Wa vefor m s a re d r a wn h ere con s id er in g id ea l d iod e, n o lea k a ge in t h e ca p a cita n ce u n d er id ea l s itu a t ion s wh ich will b e d ifferen t in p r a ct ica l s it u a t ion s . Ne gat ive c lam pin g:

In a n ega t ive cla m p in g cir cu it p ola r ity of d iod e is r ever s e th a n in p os it ive cla m p in g. In ou r s ign a l in p u t s win gs fr om -2 V t o +2 V (p ea k t o p ea k 4 V). Diod e tu r n s ON d u r in g th e p os it ive cycle a n d ch a r ge is s t or ed in t h e ca p a citor . Ca p a cit or will ch a r ge u p t o +2 V in ou r exa m p le. Du r in g t h e n ega tive cycle t h is volt a ge will b e in s er ies with t h e in p u t volt a ge a n d gives tot a l ou t p u t -4 V d u r in g n ega t ive p ea k of th e in p u t s ign a l.


Ex pe rim e n t Pro c e du re : x x

Con n ect fu n ct ion gen er a t or with CRO. Set s in e wa ve wit h 4 V p ea k t o p ea k . E n s u r e t h a t offs et volta ge is 0 . Con n ect t h e fu n ct ion gen er a t or a t t h e in p u t of t h e cla m p in g cir cu it

x Ob s er ve ou t p u t wa vefor m s on t h e CRO for d ifferen t cla m p in g cir cu its a n d d ra w ou tp u t wa vefor m s .

:: WORKS HEET :: Draw c irc u it diagram s (as pe r c irc u it available in t h e labo rat o ry o r c irc u it c o n n e c t e d o n bre adbo ard):


Wav e fo rm s : [1 ]In p u t Wa vefor m :

Ou tp u t wa vefor m for cir cu it 1 :


Co n c lu s io n :

__________________________________________________________________ __________________________________________________________________ __________________________________________________________________ __________________________________________________________________


Qu e s t io n s : [1 ] Dr a w ou t p u t wa vefor m for th e followin g cir cu it s if in p u t of 4 V p ea k t o-p ea k wit h zer o offs et is a p p lied . C1

D2 4 Vpp

10K +2V

C1

D2 4 Vpp

10K +2V


EXPERIMENT NO. 1 2 AIM: To ob s er ve wa vefor m s a t t h e ou t p u t of clip p er cir cu it s In t ro du c t io n : Clip p in g cir cu it is u s ed t o s elect for t ra n s m is s ion t h a t p a r t of a n a r b it ra r y wa vefor m wh ich lie a b ove or b elow s om e refer en ce level. Clip p in g cir cu it “clip s ” s om e p or tion of th e wa vefor m . Clip p in g cir cu it a r e a ls o r efer red t o a s volt a ge lim iter s . Cla m p in g cir cu it p r es er ves s h a p e of t h e wa vefor m wh ile clip p in g cir cu it d oes n ot p r es er ve s h a p e of wa vefor m . Clip p in g cir cu it u s es s om e r efer en ce level. Wa vefor m a b ove or b elow t h is r efer en ce level is clip p ed . Clip p in g cir cu its a re a ls o k n own a s volt a ge lim iter or a m p lit u d e lim iter or s licer s . S om e clip p er cir cu its a re exp la in ed h ere. Po s it ive c y c le c lippe r c irc u it s : Pos itive cycle clip p er cir cu its a re s h own in t h e figu re wit h s er ies a n d s h u n t d iod e. Tr a n s fer ch a ra cter is tics a n d ou t p u t wa vefor m for s in u s oid a l in p u t is s h own .

Fo r s e rie s dio de : x x

Wh en vi(t)<0 , Diod e D is in ON con d it ion , in p u t wa vefor m is a va ila b le a t th e ou tp u t. Wh en vi(t)>0 , Diod e D is in OFF con d it ion , in p u t wa vefor m is n ot a va ila b le a t t h e ou t p u t a n d ou tp u t r em a in s zer o.


Fo r s h u n t dio de : x

Wh en vi(t)<0 , Diod e D is in ON con d it ion wh ich b yp a s s t h e s ign a l to t h e gr ou n d a n d h en ce in p u t wa vefor m is n ot a va ila b le a t t h e ou t p u t . x Wh en vi(t)>0 , Diod e D is in OFF con d it ion a n d a ct s lik e a OFF s wit ch , in p u t wa vefor m is a va ila b le a t th e ou t p u t. For n ega t ive cycle clip p er , p ola r it y of d iod e is rever s e. S e rie s dio de po s it ive c lippin g wit h po s it ive re fe re n c e : In t h e cir cu it s h own in t h e followin g figu r e, DC r eferen ce volt a ge is u s ed . Th is is u s efu l of we d o n ot wa n t to clip en t ire p os it ive cycle b u t s om e p or t ion of p os it ive h a lf cycle.

x x

Wh en vi(t) VR , Diod e D is in OFF con d ition , in p u t wa vefor m is n ot a va ila b le a t t h e ou t p u t a n d ou tp u t r em a in s zer o. Th u s p or t ion of ou t p u t cycle clip s a s s h own in th e wa vefor m .

S e rie s dio de po s it ive c lippin g wit h n e gat ive re fe re n c e : If wa n t to clip en t ire p os it ive h a lf cycle a lon g wit h s om e p or t ion of t h e n ega tive cycle t h en n ega t ive DC refer en ce ca n b e u s ed a s s h own in th e followin g figu r e. In th is ca s e on ly s om e p or t ion of n ega t ive cycle p a s s es t o th e ou tp u t.


x x

Wh en vi(t)<-VR , Diod e D is in ON con d ition , in p u t wa vefor m is a va ila b le a t th e ou tp u t. Wh en vi(t )> -VR , Diod e D is in OFF con d ition , in p u t wa vefor m is n ot a va ila b le a t t h e ou tp u t a n d ou t p u t r em a in s con s ta n t equ a l t o VR . Th u s en t ir e p os itive cycle a n d s om e p or t ion of n ega t ive cycle b elow –VR clip s .

S e rie s dio de n e gat ive c lippin g wit h re fe re n c e : Nega t ive clip p in g ca n b e a ch ieved b y ch a n gin g p ola r it y of th e d iod e. Nega t ive clip p er with n ega tive r efer en ce volt a ge is s h own in t h e followin g figu r e. Th is will clip s om e p or t ion of n ega t ive cycle.

x

Wh en vi(t)>-VR , Diod e D is in ON con d ition , in p u t wa vefor m is a va ila b le a t th e ou tp u t. x Wh en vi(t )< -VR , Diod e D is in OFF con d ition , in p u t wa vefor m is n ot a va ila b le a t t h e ou tp u t a n d ou tp u t volt a ge r em a in s con s t a n t wh ich is equ a l to –VR. S h u n t dio de po s it ive c lippin g wit h n e gat ive re fe re n c e vo lt age : S h u n t d iod e p os itive clip p in g wit h n ega t ive referen ce volta ge is a s s h own in t h e followin g cir cu it . Th is will clip en t ire p os it ive cycle a n d s om e p or t ion of n ega t ive cycle a s s h own in th e wa vefor m .

x x

Wh en vi(t)<-VR , Diod e D is in OFF con d it ion (op en cir cu it) a n d in p u t wa vefor m is a va ila b le a t t h e ou tp u t. Wh en vi(t)> -VR , Diod e D is in ON con d ition , in p u t wa vefor m is n ot a va ila b le a t t h e ou t p u t a n d n ega t ive volt a ge –VR is exten d ed t o t h e ou t p u t . Ou t p u t volt a ge r em a in s con s ta n t equ a l t o VR . Th u s en t ir e p os it ive cycle a n d s om e p or t ion of n ega t ive cycle b elow –VR clip s .


S h u n t dio de n e gat iv e c lippin g wit h n e gat ive re fe re n c e : Nega t ive clip p in g with n ega t ive r efer en ce volt a ge ca n b e a ch ieved b y r ever s in g p ola r it y of t h e d iod e. S om e p or tion of n ega t ive cycle clip s .

x x

Wh en vi(t)>-VR , Diod e D is in OFF con d it ion (op en cir cu it) a n d in p u t wa vefor m is a va ila b le a t t h e ou tp u t. Wh en vi(t ) < -VR , Diod e D is in ON con d it ion , in p u t wa vefor m is n ot a va ila b le a t t h e ou t p u t a n d n ega t ive volt a ge –VR is exten d ed t o t h e ou t p u t . Ou t p u t volt a ge r em a in s con s ta n t equ a l t o VR . Th u s en t ir e p os it ive cycle a n d s om e p or t ion of n ega t ive cycle b elow –VR clip s .

Ex pe rim e n t Pro c e du re : x x

Con n ect fu n ct ion gen er a t or with CRO. Set s in e wa ve wit h 6 V p ea k t o p ea k . E n s u r e t h a t offs et volta ge is 0 . Con n ect t h e fu n ct ion gen er a t or a t t h e in p u t of t h e clip p in g cir cu it

x Ob s er ve ou t p u t wa vefor m s on t h e CRO for d ifferen t clip p in g cir cu it s a n d d ra w ou tp u t wa vefor m s .

:: WORKS HEET :: Draw c irc u it diagram s (as pe r c irc u it available in t h e labo rat o ry o r c irc u it c o n n e c t e d o n bre adbo ard): Cir cu it 1 :


Cir cu it 2 :

Cir cu it 3 :

Cir cu it 4 :


Wav e fo rm s : [1 ]In p u t Wa vefor m :






Co n c lu s io n :

__________________________________________________________________ __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ Qu e s t io n s : [1 ] Dr a w ou t p u t wa vefor m for t h e followin g cir cu it s if s in u s oid a l s ign a l of 6 V p ea k -t o-p ea k wit h zer o offs et is a p p lied a t th e in p u t . Con s id er r efer en ce volta ge VR = +2 V


Consider Zener voltage 2.5V

VR = -3 V


EXPERIMENT NO. 1 3 AIM: To ob ta in com m on em itter ch a ra cter is tics of NPN tr a n s is t or In t ro du c t io n : Tr a n s is tor is t h r ee t er m in a l a ct ive d evice h a vin g ter m in a ls collector , b a s e a n d em it ter . Tr a n s is t or is wid ely u s ed in a m p lifier , os cilla t or , elect r on ic s wit ch a n d s o m a n y oth er elect r on ics cir cu it s for va r iety of a p p lica t ion s . To u n d er s ta n d op er a t ion of t h e t ra n s is tor , we u s e t h ree con figu r a t ion s com m on em it ter , com m on b a s e a n d com m on collect or . In t h is p r a ct ica l, we will u n d er s ta n d com m on em it ter con figu ra tion . As t h e n a m e s u gges t, em it ter is com m on b et ween in p u t a n d ou t p u t. In p u t is a p p lied t o b a s e a n d ou tp u t is ta k en fr om collect or .

We will ob ta in in p u t ch a r a cter is t ics a n d ou t p u t ch a r a cter is t ics of com m on em it ter (CE ) con figu r a t ion . We will con n ect va r ia b le DC p ower s u p p ly a t VBB a n d VCC t o ob ta in ch a ra cter is tics . In p u t volta ge in CE con figu r a t ion is b a s eem it ter volta ge Vb e a n d in p u t cu r r en t is b a s e cu r ren t Ib . Ou t p u t volt a ge in CE con figu r a t ion is collect or t o em itter volt a ge VCE a n d ou t p u t cu r r en t is collect or cu r ren t Ic. We will u s e m u lt i-m eter to m ea s u r e t h es e volta ges a n d cu r r en t s for d iffer en t ch a ra cter is t ics . Collect or to em it ter ju n ction is r evers e b ia s ed a n d b a s e t o em it ter ju n ct ion is for wa r d b ia s ed . Th e CE con figu r a t ion is wid ely u s ed in a m p lifier cir cu its b eca u s e it p r ovid es volta ge ga in a s well a s cu r ren t ga in . In CB con figu r a tion cu r r en t ga in is les s t h a n u n it y. In CC con figu r a t ion volta ge ga in is les s t h a n u n it y. In p u t res is t a n ce of CE con figu r a t ion is les s th a n CC con figu r a tion a n d m ore t h a n CB con figu r a t ion . Ou tp u t r es is ta n ce of CE con figu r a t ion is m or e t h a n CC con figu r a t ion a n d les s t h a n CB con figu r a t ion .


:: WORKS HEET :: Circ u it s e t u p fo r in pu t c h arac t e ris t ic s : 1K

100K

Ib

A Vbe VBB

Vcc

Q1

V

Ex pe rim e n t Pro c e du re :

x Con n ect cir cu it a s s h own in t h e cir cu it d ia gra m for in p u t ch a ra cter is tics

x Con n ect va r ia b le p ower s u p p ly 0 -3 0 V a t b a s e cir cu it a n d collect or cir cu it .

x Keep Vcc fix a t 0 V (Or d o n ot con n ect Vcc) x In cr ea s e VBB fr om 0 V t o 2 0 V, n ot e d own rea d in gs of b a s e cu r ren t Ib a n d b a s e t o em it ter volt a ge Vb e in th e ob s er va t ion ta b le.

x Rep ea t a b ove p r oced u r e for Vcc = +5 V a n d Vcc = +1 0 V x Dr a w in p u t ch a ra cter is t ics cu r ve. Plot Vb e on X a xis a n d Ib on Y a xis . Obs e rvat io n t able : Tr a n s is tor : __________ S r. No . Vc c = 0 V Vbe

Vc c = +5 V Ib

Vbe

Vc c =+1 0 V Ib

Vbe

Ib

1 2 3 4 5 6


In pu t Ch arac t e ris t ic s :

Circ u it s e t u p fo r o u t pu t c h arac t e ris t ic s : Ic 1K

100K

A

Ib

A Vbe

Q1

V

Vcc Vce

VBB


x Con n ect cir cu it a s s h own in t h e cir cu it d ia gra m for ou t p u t ch a ra cter is tics


x Keep b a s e cu r r en t fix (In itia lly 0 ) x In cr ea s e VCC fr om 0 V t o 3 0 V, n ot e d own rea d in gs of collect or cu r r en t Ic a n d collect or t o em itt er volta ge Vce in t h e ob s er va t ion ta b le.

x Rep ea t a b ove p r oced u r e for b a s e cu r r en ts Ib = 5 µA, 5 0 µA, 1 0 0 µA. In cr ea s e b a s e cu r ren t b y in cr ea s in g VBB .

x Dr a w ou t p u t ch a ra cter is t ics cu r ve. Plot Vce on X a xis a n d Ic on Y a xis .


Obs e rvat io n t able : Tr a n s is tor : __________ S r. No . Ib = 0 Vc e

Ic

Ib = 5 µA Vc e

Ic

Ib = 5 0 µA

Ib = 1 0 0 µA

Vc e

Vc e

Ic

Ic

1 2 3 4 5 6 7 8 Ou t pu t Ch arac t e ris t ic s :


Co n c lu s io n :

__________________________________________________________________ __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ Qu e s t io n s : [1 ] How to ch eck t ra n s is tor wit h h elp of m u ltim eter ?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ __________________________________________________________________ [2 ] How to ch eck t yp e of t r a n s is t or (NPN or PNP) with h elp of m u lt im eter ?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ __________________________________________________________________ [3 ] Defin e cu r ren t ga in of t h e t ra n s is tor in CE con figu r a t ion . Wh a t is t h e DC cu r r en t ga in you ob t a in in t h is p r a ct ica l?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ WZdDEd 'KsZEDEdE'/EZ/E'K>>' Z:

EXPERIMENT NO. 1 4 AIM: To ob ta in com m on b a s e ch a r a cter is t ics of NPN t r a n s is tor In t ro du c t io n : In a com m on b a s e con figu r a tion , b a s e t e r m in a l is c o m m o n b e t w e e n in p u t a n d o u t p u t . Th e o u t p u t is t a k e n fr o m c o lle c t o r a n d t h e in p u t vo lt a ge is a p p lie d b e t w e e n e m it t e r a n d b a s e . Th e b a s e is gr o u n d e d b e c a u s e it is c o m m o n . To o b t a in o u t p u t c h a r a c t e r is t ic s , w e w ill m e a s u r e c o lle c t o r c u r r e n t fo r d iffe r e n t va lu e o f c o lle c t o r t o b a s e vo lt a ge (V C B ). In p u t c u r r e n t is e m it t e r c u r r e n t Ie a n d in p u t vo lt a ge is Ve b . To p lo t in p u t c h a r a c t e r is t ic s w e w ill p lo t Ve b ve r s u s Ie . C u r r e n t ga in fo r C B c o n fig u r a t io n is le s s t h a n u n it y . C B c o n figu r a t io n is u s e d in c o m m o n b a s e a m p lifie r t o o b t a in vo lt a ge ga in . O u t p u t im p e d a n c e o f c o m m o n b a s e c o n fig u r a t io n is ve r y h ig h . C B a m p lifie r is u s e d in m u lt i- s t a ge a m p lifie r w h e r e im p e d a n c e m a t c h in g is r e q u ir e d b e t w e e n d iffe r e n t s t a ge s . Ci rc u i t d i a g ra m t o o b t a i n i n p u t c h a ra c t e ri s t i c s : 10K

Ie

VEE

Veb

1K

Q1

A

Vcc

V

Ci rc u i t d i a g ra m t o o b t a i n o u t p u t c h a ra c t e ri s t i c s : 10K

Ie

A

VEE

Ic 1K

Q1

V

A

Vcc Vcb


:: WORKS HEET :: Ex pe rim e n t Pro c e du re t o o bt ain in pu t c h arac t e ris t ic s :


x Con n ect va r ia b le p ower s u p p ly 0 -3 0 V (VE E ) a t em it ter b a s e cir cu it a n d a n oth er p ower s u p p ly 0 -3 0 V a t collect or b a s e cir cu it (Vcc).

x Keep Vcc fix a t 0 V (Or d o n ot con n ect Vcc) x In cr ea s e VE E fr om 0 V t o 2 0 V, n ot e d own rea d in gs of em it ter cu r r en t Ie a n d em it ter to b a s e volt a ge Veb in th e ob s er va t ion ta b le.

x Rep ea t a b ove p r oced u r e for Vcc = +5 V a n d Vcc = +1 0 V x Dr a w in p u t ch a ra cter is t ics cu r ve. Plot Veb on X a xis a n d Ie on Y a xis . Ex pe rim e n t Pro c e du re t o o bt ain o u t put c h arac t e ris t ic s :


x Con n ect va r ia b le p ower s u p p ly 0 -3 0 V a t em it ter cir cu it a n d collect or cir cu it .

x Keep em itter cu r ren t fix (In it ia lly 0 ) x In cr ea s e VCC fr om 0 V t o 3 0 V, n ot e d own rea d in gs of collect or cu r r en t Ic a n d collect or t o b a s e volta ge Vcb in t h e ob s er va t ion ta b le.

x Rep ea t a b ove p r oced u r e for b a s e cu r r en ts Ie = 1 m A, 5 m A a n d 1 0 m A. In cr ea s e em it ter cu rr en t b y in crea s in g VE E .

x Dr a w ou t p u t ch a ra cter is t ics cu r ve. Plot Vcb on X a xis a n d Ic on Y a xis . Obs e rvat io n t able fo r in pu t c h arac t e ris t ic s : Tr a n s is tor : __________ S r. No . Vc c = 0 V Vc c = +5 V Ve b

Ie

Ve b

Ie

1 2 3 4 5 6


Vc c =+1 0 V Ve b

Ie


Obs e rvat io n t able fo r o u t pu t c h arac t e ris t ic s : Tr a n s is tor : __________ S r. No .

Ie = 0 Vc b

Ic

Ie = 1 m A

Ie = 5 m A

Ie = 1 0 m A

Vc b

Vc b

Vc b

Ic

Ic

Ic

1 2 3

4 5 6 7 8


Ou t pu t Ch arac t e ris t ic s :

Co n c lu s io n :

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ ___________________________________________________________________ Qu e s t io n s : [1 ] Wh a t is ea r ly effect? Ha ve you ob s erved ea r ly effect in you r exp er im en t ?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________


_____________________________________________________________________ _____________________________________________________________________ __________________________________________________________________ [2 ] Com p a re com m on b a s e a n d com m on em it ter con figu r a t ion

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ __________________________________________________________________ [3 ] J u s t ify t h e s ta tem en t : Com m on b a s e a m p lifier is u s ed a s b u ffer

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________

[3 ] Wh a t is t h e va lu e of p h a s e s h ift b et ween in p u t a n d ou t p u t s ign a l in com m on b a s e a n d com m on em it ter a m p lifier ?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________


EXPERIMENT NO. 1 5 AIM: To ob ta in com m on collect or ch a ra ct er is t ics of NPN t ra n s is tor In t ro du c t io n : In com m on collector con figu r a tion , collector ter m in a l is com m on b et ween in p u t a n d ou t p u t . In p u t is a p p lied b etween b a s e a n d collect or . Ou t p u t is ta k en fr om em itter a n d collector . Volta ge ga in of CC con figu r a t ion is les s th a n u n it y. CC a m p lifier is u s ed t o p r ovid e cu r ren t ga in . It h a s ver y h igh in p u t im p ed a n ce a n d ver y low ou t p u t res is t a n ce h en ce it is u s ed to con n ect low im p ed a n ce loa d to s ou r ce wh ich is h a vin g h igh ou t p u t im p ed a n ce. Th u s , it ca n b e u s ed a s im p ed a n ce m a t ch in g. E m it t er cu r r en t is a p p r oxim a tely equ a l t o collector cu r r en t , h en ce ou t p u t ch a ra cter is tics of CC con figu r a t ion is ver y m u ch s a m e a s CE con figu r a tion . However , in p u t ch a r a cter is t ics of CE a n d CC a r e qu ite d ifferen t . Ci rc u i t d i a g ra m t o o b t a i n i n p u t c h a ra c t e ri s t i c s :

Vcb 100K

V

Ib

A

Vcc

Q1

VBB

1K

Ci rc u i t d i a g ra m t o o b t a i n o u t p u t c h a ra c t e ri s t i c s :

100K

Ib

A

Q1

Vcc

V

VBB

Vce 1K

A

Ie


:: WORKS HEET :: Ex pe rim e n t Pro c e du re t o o bt ain in pu t c h arac t e ris t ic s :


x Con n ect va r ia b le p ower s u p p ly 0 -3 0 V (VBB ) a t b a s e-em it ter cir cu it a n d a n oth er p ower s u p p ly 0 -3 0 V a t collect or em it ter cir cu it (Vcc).

x Keep Vce fix a t 0 V (Or d o n ot con n ect Vcc) x In cr ea s e VBB fr om 0 V t o 2 0 V, n ot e d own rea d in gs of b a s e cu r r en t Ib a n d collect or t o b a s e volta ge (Vcb ) in t h e ob s er va tion ta b le.

x Rep ea t a b ove p r oced u r e for Vce = +1 V a n d Vce = +2 V x Dr a w in p u t ch a ra cter is t ics cu r ve. Plot Vcb on X a xis a n d Ib on Y a xis . Ex pe rim e n t Pro c e du re t o o bt ain o u t put c h arac t e ris t ic s :



x Keep b a s e cu r ren t fix (In itia lly 0 ) x In cr ea s e VCC fr om 0 V t o 3 0 V, n ot e d own rea d in gs of em it ter cu r r en t Ic a n d collect or t o em itter volta ge Vce in t h e ob s er va t ion ta b le.

x Rep ea t a b ove p r oced u r e for b a s e cu r r en ts Ib = 1 0 µA, 5 0 µA a n d 1 0 0 µA. In cr ea s e b a s e cu r r en t b y in crea s in g VBB .

x Dr a w ou t p u t ch a ra cter is t ics cu r ve. Plot Vce on X a xis a n d Ie on Y a xis for d iffer en t va lu es of b a s e cu r r en t s . Obs e rvat io n t able fo r in pu t c h arac t e ris t ic s : Tr a n s is tor : __________ S r. No . Vc e = 0 V Vc e = +1 V Vc b

Ib

Vc b

Ib

Vc e =+2 V Vc b

Ib

1 2 3 4 5 6 ^/>dZKE/^>KZdKZzDEh>


Obs e rvat io n t able fo r o u t pu t c h arac t e ris t ic s : Tr a n s is tor : __________ S r. No .

Ib = 0 µA

Ib = 1 0 µA

Ib = 5 0 µA

Ib = 1 0 0 µA

Vc e

Vc e

Vc e

Vc e

Ie

Ie

1 2 3

4 5 6 7 8


Ie

Ie

Ou t pu t Ch arac t e ris t ic s :

Co n c lu s io n :

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ ___________________________________________________________________ Qu e s t io n s : [1 ] Wh a t is t h e in p u t a n d ou t p u t im p ed a n ce of CC con figu r a tion com p a r ed t o CE a n d CB con figu r a t ion ?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ ^/>dZKE/^>KZdKZzDEh>

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ __________________________________________________________________ [2 ] J u s t ify: It is b et ter t o u s e com m on -collector a m p lifier b etween com m on em it ter a m p lifier a n d loa d -s p ea k er .

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ __________________________________________________________________ [3 ] Com p a re volta ge ga in a n d cu r r en t ga in of CC a m p lifier with CB a n d CE a m p lifier .

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ __________________________________________________________________ [4 ] Wh a t is em it ter follower ?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________


EXPERIMENT NO. 1 6 AIM: To u n d er s ta n d wor k in g of t r a n s is t or a s a s witch . To d r a w DC loa d lin e for given cir cu it In t ro du c t io n : Tr a n s is tor ca n b e op era ted in th ree r egion : cu t-off r egion , a ct ive region a n d s a t u ra t ion r egion . Wh ile u s in g t ra n s is tor in a m p lifier cir cu it, we a re u s in g a ct ive region . If t r a n s is t or op era ted in cu t -off a n d s a tu r a t ion r egion in a m p lifier , clip p in g of wa vefor m s will occu r . Wh en we u s e tr a n s is t or a s a s wit ch , on ly two r egion s cu t -off a n d s a tu r a t ion a re u s ed . In s a tu r a t ion r egion t ra n s is t or a cts a s ON s witch . In cu t -off r egion , t ra n s is tor a ct s a s OFF s wit ch . We a r e u s in g on ly two p oin t s of DC loa d lin e wh ile u s in g t r a n s is t or a s a s wit ch . Circ u it diagram : 1K

A

Ib LED SW

10K

Ib

A +5V

Q1

12V

V Vce

Ex pe rim e n t Pro c e du re t o o bt ain in pu t c h arac t e ris t ic s :


x Ad ju s t collect or s u p p ly Vcc = +1 2 V a n d b a s e s u p p ly VBB =+5 V x You m a y u s e b a s e volt a ge s u p p ly s wit ch in s tea d of s wit ch s h own in th e cir cu it d ia gr a m .

x Mea s u r e b a s e cu r r en t wh en s wit ch is OFF (It will b e zer o). Mea s u re collect or cu r r en t a n d volt a ge b et ween collector a n d em itter . LE D is off b eca u s e t ra n s is t or is in cu t-off r egion ,

x Now a p p ly b a s e volta ge +5 V, LE D will b e ON. Mea s u r e collector cu r r en t a n d collect or -em it ter volta ge. Tr a n s is tor is in s a t u ra t ion r egion .


:: WORKS HEET :: Obs e rvat io n s : [1 ] S wit ch off (VBB =0 ):

Ib = _________

[2 ] S wit ch ON (VBB =+5 V):

VCE = __________ Ic = ________

Ib = _________

VCE = __________ Ic = ________

Dr a w DC loa d lin e a n d s h ow s a t u ra tion a n d cu t off p oin t s :

Co n c lu s io n :

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ ___________________________________________________________________


Qu e s t io n s : [1 ] Wh a t a r e th e a p p lica t ion s of tr a n s is tor a s a s witch ?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ [2 ] Wh a t s h ou ld b e r a t io of collect or res is t a n ce t o b a s e r es is ta n ce wh ile d es ign in g t ra n s is tor s wit ch ? Wh a t is h a r d s a tu r a t ion ?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ [3 ] Dr a w ou tp u t wa vefor m wh en followin g wa vefor m is a p p lied a t t h e b a s e cir cu it . In p u t wa vefor m a p p lied a t b a s e: s s



EXPERIMENT NO. 1 7 AIM: To ob s er ve in p u t -ou tp u t wa vefor m s of com m on em it ter (CE ) a m p lifier . To m ea s u r e ga in of a m p lifier a t d ifferen t frequ en cies a n d p lot fr equ en cy res p on s e In t ro du c t io n : Com m on em itter a m p lifier is u s ed t o a m p lify wea k s ign a l. It u tilizes en er gy fr om DC p ower s u p p ly t o a m p lify in p u t AC s ign a l. Bia s in g of tr a n s is t or is d on e t o t ie Q p oin t a t t h e m id d le of th e loa d lin e. In t h e cir cu it s h own , volt a ge d ivid er b ia s is for m ed u s in g r es is t or s 1 0 K a n d 2 .2 K. Du r in g p os itive cycle, for wa r d b ia s of b a s e-em itt er ju n ction in crea s es a n d b a s e cu r r en t in crea s es . Q p oin t m oves in u p wa r d d ir ect ion on loa d lin e a n d collect or cu r ren t in cr ea s es t im es t h a n b a s e cu r r en t . ( is cu r r en t ga in ). Collect or r es is tor d r op IcRc in cr ea s es d u e t o in cr ea s e in collect or cu r ren t Ic. Th is will r ed u ce collect or volta ge. Th u s d u r in g p os it ive in p u t cycle, we get n ega tive ou t p u t cycle. Wh en in p u t is n ega tive cycle, for wa rd b ia s of b a s eem it ter ju n ct ion a n d b a s e cu r ren t will red u ce. Collect or cu r r en t red u ces (Q p oin t m oves d own s id e). Du e t o d ecr ea s e in collect or cu r r en t , collect or r es is ta n ce volta ge d r op IcRc red u ces a n d collect or volta ge in cr ea s es . Ch a n ge in collector volt a ge is m u ch h igh er th a n a p p lied b a s e volt a ge b eca u s e les s b a s e cu r r en t va r ia tion ca u s es la r ge collect or cu r r en t va r ia t ion d u e t o cu r r en t ga in B . Th is la r ge collector cu r r en t fu r th er m u lt ip lied b y collect or r es is ta n ce Rc wh ich p r ovid es la r ge volta ge ou t p u t . Th u s CE a m p lifier p r ovid es volta ge ga in a n d a m p lifies th e in p u t s ign a l. Wit h ou t em it ter r es is t a n ce ga in of a m p lifier is h igh es t b u t it is n ot s ta b le. E m itt er res is ta n ce is u s ed t o p r ovid e s t a b ilit y. To com p en s a te effect of em it ter r es is ta n ce em itter b yp a s s ca p a cit or is u s ed wh ich p r ovid es AC gr ou n d t o th e em it ter . Th is will in cr ea s e ga in of a m p lifier . CE a m p lifier d oes n ot p r ovid e con s ta n t volt a ge ga in a t a ll fr equ en cies . Du e t o em it ter b yp a s s a n d cou p lin g ca p a cit or s r ed u ces ga in of a m p lifier a t low fr equ en cy. Rea cta n ce of ca p a cit or is h igh a t low fr equ en cy, h en ce em it ter b yp a s s ca p a citor d oes n ot p r ovid e p er fect AC gr ou n d (E m it t er im p ed a n ce is h igh ). Th er e is volta ge d rop a cr os s cou p lin g ca p a cit or a t low fr equ en cy b eca u s e of h igh r ea cta n ce a t low fr equ en cies . Ga in of CE a m p lifier a ls o red u ces a t ver y h igh frequ en cy b eca u s e of s t ra y ca p a cit a n ces . Au d io fr equ en cy t ra n s is t or s lik e AC1 2 7 , AC1 2 8 wor k s for a u d io fr equ en cy r a n ge. It d oes n ot p r ovid e la r ge volta ge ga in for fr equ en cy gr ea ter t h a n 2 0 KHz. Med iu m fr equ en cy t r a n s is t or s a re BC1 4 7 / BC1 4 8 / BC5 4 7 / BC5 4 8 p r ovid es volt a ge ga in u p to 5 0 0 KHz. High fr equ en cy tr a n s is t or s lik e BF1 9 4 / BF5 9 4 / BF2 0 0 p r ovid es ga in a t r a d io frequ en cies in th e MHz r a n ge.


If we a p p ly la r ge s ign a l a t t h e in p u t of CE a m p lifier , t r a n s is t or d r iven in to s a t u r a t ion r egion d u r in g p os it ive p ea k a n d cu t-off r egion d u r in g n ega tive p ea k (Q p oin t r ea ch es t o s a tu r a t ion a n d cu t -off p oin t s ). Du e to t h is clip p in g occu r s in a m p lified s ign a l. S o we h a ve t o a p p ly s m a ll s ign a l a t t h e in p u t a n d en s u r e th a t tr a n s is t or op era tes in a ct ive region . Circ u it diagram :

+12V

Function Generator

22K

1K

10uF

CRO

10uF BC547

4.7K

100uF 100

Ex pe rim e n t al pro c e du re : x

Con n ect fu n ct ion gen er a t or a t t h e in p u t of t h e a m p lifier cir cu it.

x

S et in p u t volta ge 1 0 m V a n d frequ en cy 1 0 0 Hz.

x

Con n ect CRO a t t h e ou t p u t of t h e a m p lifier cir cu it .

x

Ob s er ve a m p lified s ign a l a n d m ea s u r e ou t p u t volta ge

x

In cr ea s e frequ en cy fr om t h e fu n ct ion gen era tor a n d r ep ea t a b ove s tep

x

Note d own r ea d in gs of ou t p u t volt a ge in th e ob s er va t ion t a b le for fr equ en cy ra n ge fr om 1 0 0 Hz t o 1 0 MHz

x

Ca lcu la te volta ge ga in for d iffer en t fr equ en cies a n d ga in in d B. Plot fr equ en cy res p on s e.


:: WORKS HEET :: Draw c irc u it diagram fro m t h e bo ard available in t h e labo rat o ry :

Obs e rvat io n t able : In p u t volta ge: Vi = 1 0 m V S r. No.

Frequ en cy a t t h e in p u t

Ou t p u t volt a ge Vo

Ga in A = Vo/ Vi

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12.


Ga in in 2 0 log1 0 (A)

d B=

Dr a w fr equ en cy res p on s e of CE a m p lifier (you ca n a ls o u s e loga r ith m ic gr a p h or u s e log s ca le)

Co n c lu s io n :

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ ___________________________________________________________________ Qu e s t io n s : [1 ] Wh a t will b e em itt er cu r r en t in t h e given cir cu it d ia gr a m in a b s en ce of in p u t AC s ign a l?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ ^/>dZKE/^>KZdKZzDEh>

_____________________________________________________________________ _____________________________________________________________________ [2 ] Dr a w DC loa d lin e of CE a m p lifier circu it . S h ow Q p oin t on it.

[3 ] Dr a w ou tp u t wa vefor m wh en followin g wa vefor m is a p p lied a t t h e CE a m p lifier cir cu it In p u t wa vefor m a p p lied a t b a s e: (Pea k to p ea k volta ge is 2 V)



[4 ] Wh a t is b a n d wid th ? Wh a t is t h e a p p roxim a te b a n d wid t h of CE a m p lifier t h a t you h a ve u s ed d u r in g you r p ra ctica l.

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ [5 ] Wh a t is t h e effect on ga in of a m p lifier if va lu e of Rc in crea s es ?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ [6 ] Wh a t a r e th e d ifferen t b ia s in g m et h od s ?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ [7 ] Wh a t h a p p en s if em itter b yp a s s ca p a cit or is r em oved fr om t h e cir cu it ?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ ^/>dZKE/^>KZdKZzDEh>

EXPERIMENT NO. 1 8 AIM: To ob s er ve in p u t -ou t p u t wa vefor m s of com m on collector (CC) a m p lifier . To m ea s u r e ga in of a m p lifier a t d ifferen t frequ en cies a n d p lot fr equ en cy res p on s e In t ro du c t io n : Th e com m on collect or (CC) a m p lifier is a ls o k n own a s em it ter follower . It is u s ed a s a cu r ren t a m p lifier . Volta ge ga in of CC a m p lifier is les s t h a n u n ity wh ile cu r r en t JDLQLV &&DPSOLILHUKDVKLJKLQSXWLPSHGDQFHDQGORZ ou t p u t im p ed a n ce. Th er e is n o p h a s e r ever s a l b etween in p u t a n d ou t p u t . Circ u it diagram :

+12V

Function Generator

10uF

27K

CRO

10uF SL-100

39K

2.7K


Mea s u r e E m itter volt a ge in a b s en ce of in p u t AC s ign a l.

x


x

S et in p u t volta ge 1 V a n d fr equ en cy 1 0 0 Hz.

x


x

Ob s er ve ou t p u t s ign a l a n d m ea s u r e ou t p u t volta ge

x

Dr a w in p u t a n d ou tp u t s ign a l



Obs e rvat io n s : DC Volt a ge in a b s en ce of in p u t s ign a l: VE = ______ V AC In p u t volta ge: Vi = 1 V In p u t Wa vefor m

Ou t p u t Wa vefor m


Co n c lu s io n :

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ ___________________________________________________________________ Qu e s t io n s : [1 ] Wh a t will b e em itt er volta ge a n d cu r r en t in t h e given cir cu it d ia gra m in a b s en ce of in p u t AC s ign a l?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ [2 ] Wh a t is t h e equ a t ion of cu r r en t ga in in CC a m p lifier ? Wh a t is t h e cu r r en t ga in of CC a m p lifier u s ed in la b ora t ory?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ [3 ] Ca n we con n ect lou d s p ea k er in s tea d of em it ter res is ta n ce?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________


EXPERIMENT NO. 1 9 AIM: To m ea s u re ga in of two s ta ge RC cou p led a m p lifier In t ro du c t io n : To a ch ieve h igh er ga in , we ca n u s e m u lt i-s ta ge a m p lifier wh ere ou t p u t of on e a m p lifier is con n ected t o in p u t of n ext a m p lifier . Am p lifier s a re con n ected in ca s ca d e a r r a n gem en t s o it is a ls o ca lled ca s ca d e a m p lifier . Ou tp u t of fir s t a m p lifier is con n ected t o in p u t of s econ d a m p lifier b y cou p lin g d evice lik e cou p lin g ca p a cit or . Dir ect cou p lin g or tr a n s for m er cou p lin g is a ls o u s ed . Ca p a cit or cou p lin g is u s ed to cou p le AC s ign a l fr om ou t p u t of fir s t a m p lifier t o in p u t of s econ d a m p lifier . Cou p lin g ca p a cit or d oes n ot p a s s DC s ign a l s o DC b ia s in g of s econ d s ta ge is n ot a ffected b y fir s t s t a ge a n d vice-ver s a . In th is p r a ct ica l, we will u s e ca p a cit or cou p lin g wh ich is a ls o k n own a s t wo s t a ge RC cou p led a m p lifier . Typ ica l cir cu it d ia gra m is s h own b elow: +12V

22K

Function Generator

+12V

1K

10uF

22K

1K

10uF

CRO

10uF BC547

V2

V3

BC547

V1 4.7K

100uF 100

4.7K

100uF 100

In t h is cir cu it d ia gra m , ou tp u t of fir s t s ta ge is con n ected t o in p u t of t h e s econ d s t a ge b y cou p lin g ca p a cit or of 1 0 µF. RC n et wor k is for m ed b y t h is cou p lin g ca p a citor a n d volt a ge d ivid er b ia s of th e n ext s t a ge. In p u t s ign a l V1 is a m p lified b y fir s t a m p lifier . Am p lified s ign a l fr om fir s t a m p lifier is V2 wh ich is fu r th er a m p lified b y s econ d a m p lifier . Ou t p u t s ign a l fr om t h e s econ d a m p lifier is V3 . If ga in of a m p lifier 1 is A1 t h en V2 =A1 V1 . If ga in of a m p lifier 2 is A2 t h en V3 =A2 V2 . Fr om t h is r ela t ion s h ip , V3 =A1 A2 V1 . Th is th eoret ica l overa ll ga in of ca s ca d e a m p lifier is A = V3 / V1 = A1 A2 . However p r a ctica lly over a ll ga in is s ligh t ly les s t h a n A1 A2 b eca u s e of loa d in g effect of s econ d s ta ge on th e fir s t s ta ge. Overa ll b a n d wid t h of a m p lifier will d ecrea s e. ^/>dZKE/^>KZdKZzDEh>



x

S et in p u t volta ge V1 =1 m V a n d fr equ en cy 1 0 0 Hz.

x

Con n ect CRO a t t h e ou t p u t of t h e fir s t a m p lifier cir cu it a t p oin t V2 .

x

Ob s er ve a m p lified s ign a l a n d m ea s u r e ou t p u t volta ge a t V2

x

Fin d ou t ga in of fir s t a m p lifier A1 =V2 / V1 .

x

Ob s er ve a m p lified s ign a l a t t h e ou tp u t of s econ d a m p lifier a n d m ea s u re ou t p u t volta ge a t V3

x

Fin d ou t ga in of s econ d a m p lifier A2 =V3 / V2 .

x

Fin d overa ll ga in of a m p lifier A = V3 / V1 = A1 A2

x

In cr ea s e frequ en cy fr om t h e fu n ction gen era tor a n d r ep ea t a b ove s tep s

x

Note d own r ea d in gs of ou t p u t volt a ge in th e ob s er va t ion t a b le for fr equ en cy ra n ge fr om 1 0 0 Hz t o 1 0 MHz

x

Ca lcu la te volta ge ga in A1 a n d A2 for d ifferen t frequ en cies a n d ga in in d B. Plot fr equ en cy res p on s e.



Obs e rvat io n t able : In p u t volta ge: V1 = 1 0 m V S r. No.

Fr eq. a t th e in p u t

Ou t p u t volt a ge V2

Ou t p u t volt a ge V3

Ga in A1 =V2 / V1

Ga in A2 =V3 / V2

A=A1 A2

A dB

in

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

Dr a w fr equ en cy res p on s e of CE a m p lifier (you ca n a ls o u s e loga r ith m ic gr a p h or u s e log s ca le)


Co n c lu s io n :

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ ___________________________________________________________________ Qu e s t io n s : [1 ] Wh a t a r e th e a d va n ta ges of m u lt is ta ge a m p lifier ?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ [2 ] Wh a t will h a p p en if we in crea s e in p u t volta ge in t wo s ta ge RC cou p led a m p lifier u s ed in you r p r a ct ica l to 1 0 m V?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ [4 ] Wh a t a r e th e d ifferen t cou p lin g m et h od s ? Wh a t is t h e a d va n ta ge a n d d is a d va n ta ge of d ir ect cou p lin g?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________


EXPERIMENT NO. 2 0 AIM: To ob ta in ch a ra cter is t ics of field effect t ra n s is t or (FE T) In t ro du c t io n : Th e Field E ffect Tr a n s is t or (FE T) is a t h r ee ter m in a l d evice. Th r ee ter m in a ls a re Dra in (D), S ou r ce (S ) a n d Ga te (G). In FE T, cu r r en t flow is d u e t o on ly on e t yp e of ch a r ge p a r ticles , eit h er elect r on s or h oles . S o FE T is k n own a s u n ip ola r d evice. Th e n a m e “field effect” is d er ived fr om th e fa ct th a t t h e cu r r en t is con t r olled b y a n elect r ic field s et u p in th e d evice b y a n exter n a lly a p p lied volta ge. Th u s FE T is a volt a ge con t r olled d evice wh ile b ip ola r tr a n s is t or is cu r r en t con t r olled d evice. Th e Field E ffect Tr a n s is t or (FE T) ca n b e b r oa d ly cla s s ified in t o followin g ca tegor ies : &d

:

:&d

E

&d

D

W

&d

E DK^&d

DK^&d

DK^&d

W DK^&d

&d

DK^&d

E DK^&d

W DK^&d

In th is exp er im en t we will ob t a in ou t p u t ch a r a cter is t ics of N-ch a n n el FE T u s in g CS ( Com m on s ou r ce) Con figu r a t ion . It is a ls o k n own a s d r a in ch a ra cter is tics . Ba s ic con s t r u ct ion of N-ch a n n el FE T a n d it s s ym b ol a re s h own in th e followin g figu r e. Wh en ga te t o s ou r ce volta ge VGS is zer o, N t yp e ch a n n el is op en s o d r a in cu r r en t will flow t h r ou gh it. As we in cr ea s e n ega tive volta ge on t h e ga te ter m in a l, VGS =-1 V, -2 V, -3 V et c., d r a in cu r ren t r ed u ces . Th e r ed u ct ion in d r a in cu r r en t is d u e t o red u ction in wid t h of ch a n n el. As we in cr ea s e n ega tive ga te volt a ge, wid t h of d ep let ion region s p r ea d s in t h e ch a n n el. Dep letion r egion (gen era ted field d u e t o r ever s e b ia s ) d oes n ot h a ve ch a r ge ca r r ier s s o wid t h of ch a n n el will r ed u ce. As we in cr ea s e n ega t ive va lu e of VGS , p en et ra tion of d ep let ion r egion (field ) will b e m or e a n d m or e d u e t o wh ich ch a n n el b ecom es n a r r ower . At on e p oin t d ra in cu r r en t red u ces to zer o wh en en t ire ch a n n el will b e clos ed d u e to p en etr a t ion of d ep let ion r egion . Th e va lu e of VGS a t wh ich d r a in cu r ren t r ed u ces t o zer o is ca lled cu t -off volta ge VGS (off). Nor m a lly Dr a in cu r ren t ^/>dZKE/^>KZdKZzDEh>

r ed u ces t o zer o a t VGS =-Vp . Th u s VGS (off) = -VP wh er e VP is p in ch -off volt a ge. Pin ch -off volt a ge VP is t h e va lu e of volt a ge VDS a t wh ich d r a in cu r r en t b ecom es con s ta n t .

Circ u it diagram :

1K

A

Id

10K

Ig

A

Q2

0-10V

0-12V

V Vds


x Con n ect cir cu it a s s h own in t h e cir cu it d ia gra m for ou t p u t (d r a in ) ch a ra cter is tics

x Con n ect va r ia b le p ower s u p p ly 0 -1 0 V a t ga te cir cu it a n d 0 -1 2 V a t d r a in cir cu it .

x Keep ga te t o s ou r ce volt a ge zer o (VGS =0 ). WZdDEd 'KsZEDEdE'/EZ/E'K>>' Z:

x In cr ea s e d r a in s u p p ly Vd d fr om 0 V to 1 2 V, n ot e d own r ea d in gs of d r a in cu r ren t Id a n d d r a in t o s ou r ce volta ge Vd s in t h e ob s er va t ion ta b le.

x Rep ea t a b ove p r oced u r e for d ifferen t ga te t o s ou r ce volta ges VGS = -1 , -2 , -3 , -4 et c. Note d own r ea d in g of Ga te to s ou r ce volta ge a t wh ich d r a in cu r r en t r em a in s zer o. Th is is cu t -off volt a ge VGS (off).

x Note d own p in ch -off volt a ge for a ll va lu es of VGS . x Dr a w ou tp u t ch a ra cter is t ics cu r ve. Plot Vd s on X a xis a n d Id on Y a xis . :: WORKS HEET :: Draw c irc u it diagram o f t h e c irc u it available in t h e labo rat o ry :


Obs e rvat io n t able : FE T: __________ S r. No . VGS =0 V Vds

Id

VGS = -1 V

VGS = -2 V

Vds

Vds

Id

1 2 3 4 5 6 7 8 9 Ou t pu t Ch arac t e ris t ic s :


VGS = -4 V Id

Vds

Id

Co n c lu s io n :

__________________________________________________________________ __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ Qu e s t io n s : [1 ] Com p a re b ip ola r ju n ction t r a n s is t or (BJ T) a n d field effect tr a n s is t or (FE T). Dis cu s s r ela t ive a d va n ta ges a n d d is a d va n ta ges .

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ __________________________________________________________________ [2 ] Wh a t is p in ch -off volta ge? Wh a t is t h e r ela t ion s h ip b et ween d r a in cu r ren t a n d p in ch -off volta ge?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ ________________________________________________________________ ^/>dZKE/^>KZdKZzDEh>

[3 ] Wh a t is t ra n s -con d u ct a n ce? Defin e tr a n s -con d u cta n ce for FE T. Dr a w t yp ica l t r a n s con d u cta n ce cu r ve of FET fr om t h e ob s er va t ion s you h a ve t a k en for ou t p u t ch a r a cter is t ics .

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ Tr a n s con d u ct a n ce cu r ve:

[4 ] Fin d n u m b er s of a n y t wo J FE T a n d its s p ecifica t ion s fr om t h e web s ite

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________


EXPERIMENT NO. 2 1 AIM: To m ea s u r e ga in FE T com m on s ou r ce (CS ) a m p lifier In t ro du c t io n : Com m on s ou r ce FE T a m p lifier is u s ed t o a m p lify wea k s ign a l. S m a ll AC s ign a l is a p p lied a t ga te ter m in a l via cou p lin g ca p a cit or . Ga te r es is ta n ce p r ovid es s elf b ia s . In p u t AC s ign a l p r ovid es va r ia t ion s in Ga te t o s ou rce volt a ge VGS . Beca u s e of ch a n ge in VGS , d r a in cu r r en t Id a ls o ch a n ges . If we a p p ly s in u s oid a l in p u t s ign a l, s in u s oid a l va r ia t ion in d r a in cu r r en t p r od u ces s in u s oid a l ou t p u t a t d ra in t er m in a l. Du r in g p os itive in p u t s ign a l, VGS in cr ea s es wh ich will ca u s e in cr ea s e in d r a in cu r r en t . Dr a in volta ge d ecrea s es d u e t o d r op a cr os s d r a in res is t a n ce in crea s es . Th u s we get 1 8 0 0 p h a s e s h ift b et ween in p u t a n d a m p lified ou t p u t s ign a l. Ou tp u t volt a ge fr om FE T a m p lifier ca n b e given a s : Vou t = -g m Vgs R D Wh ere,

gm = t r a n s con d u cta n ce of FE T R D = Dr a in res is ta n ce Vgs = Va r ia t ion in ga t e t o s ou r ce volta ge d u e to in p u t s ign a l

Min u s s ign in th e equ a tion in d ica tes , 1 8 0 0 p h a s e s h ift . Ga in of a m p lifier is r a t io of ou t p u t volta ge to in p u t volta ge.

A

Vout Vgs

g m RD

Beca u s e of t h e n on -lin ea r t ra n s con d u ct a n ce cu r ve of FE T, CS a m p lifier d is tor t s la r ge s ign a ls . It ca n a m p lify s m a ll s ign a l with ou t in tr od u cin g n on -lin ea r it y in t o it . For la r ge s ign a l, it in t r od u ces n on -lin ea r it y ca lled s qu a r e la w d is t or t ion . Th is is d u e t o p a r a b olic tr a n s con d u cta n ce cu r ve of FE T. S wa m p in g r es is t or ca n b e u s ed wit h s ou r ce ter m in a l t o p r ovid e loca l feed b a ck . Th is will s wa m p ou t n on -lin ea r ity of t h e tr a n s con d u cta n ce cu r ve. Differen t t yp es of b ia s in g tech n iqu es a re u s ed for CS a m p lifier . Ga te b ia s is s im ila r t o b a s e b ia s in BJ T, s elf b ia s , volta ge d ivid er b ia s , cu r r en t s ou r ce b ia s et c. Cir cu it d ia gr a m of CS a m p lifier wit h s elf b ia s is s h own h ere.


Circ u it diagram :

+12V

Function Generator

4.7K 1uF

CRO

1uF

100K

100uF 270



x

S et in p u t volta ge 1 0 0 m V a n d fr equ en cy 1 0 0 Hz.

x


x

Ob s er ve ou t p u t s ign a l a n d m ea s u r e ou t p u t volta ge

x

In cr ea s e fr equ en cy of t h e in p u t s ign a l a n d r ep ea t a b ove s tep s for d ifferen t fr equ en cies :: WORKS HEET ::

Draw c irc u it diagram fro m t h e bo ard available in t h e labo rat o ry :


Obs e rvat io n t able : In p u t volta ge: Vi = 1 0 0 m V S r. No.

Frequ en cy a t t h e in p u t

Ou t p u t volt a ge Vo

Ga in A = Vo/ Vi

Ga in in 2 0 log1 0 (A)

d B=

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11.

Dr a w fr equ en cy r es p on s e of CS a m p lifier (you ca n a ls o u s e loga r ith m ic gr a p h or u s e log s ca le)


Co n c lu s io n :

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ ___________________________________________________________________ Qu e s t io n s : [1 ] Wh y ga te b ia s is n ot p r efer red for FET a m p lifier ?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ [2 ] Fr om t h e d a ta s h eet of FE T 2 N5 9 5 1 IDS S =1 0 m A a n d VGS=-3 .5 V. Ca lcu la te t h e d r a in cu r r en t of FE T for VGS =-1 V, -2 V a n d -3 V ?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ [3 ] Ca n we u s e FE T a s elect r on ic s wit ch ? If yes h ow?

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ WZdDEd 'KsZEDEdE'/EZ/E'K>>' Z:

EXPERIMENT NO. 2 2 AIM: To tes t in d ivid u a l cir cu it p r ep a r ed b y t h e s tu d en t Nam e o f t h e c irc u it : Circ u it diagram :

Lis t o f c o m po n e n t u s e d:

To t al c o s t o f c o m po n e n t :

Qu alit y o f s o lde rin g: (Rem a r k s b y t h e fa cu lt y) ^/>dZKE/^>KZdKZzDEh>

Te s t in g pro c e du re :

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ Re s u lt s : (Res u lt s d ep en d s on cir cu it d ia gra m , p r ep a re ob s er va tion t a b le, d ra w wa vefor m s a s p er you r cir cu it d ia gr a m , a t t a ch m or e p a ges if n eed ed )


Basic Electronics Lab Manual c1t6h

Overview 4q3b3c

More details 26j3b

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