- S-£;.-~i?AY).3 ~)~)ec.-t~niCb le\;",ce,6.-Con. 5452-08. ~ -

, tX-r&." (REVISED COURSE)

AU.l'Lt.lL~ ~> (4)J'1C9-BRC-8774~ '=:t

(3 Hours) [Total Marks: 100

N.B. : (1) Question Nos. 1 and 2 are compulsory.

(2) Solve any three questions from remaining.

(3) Assume suitable additional data wherever necessary.

1. Design single stage R-C coupled CE amplifier using BJTto meet the following" 20specifications. IA" I> 150. SIca < 10. FL =20 Hz. Va = 5 V RMS Vcc = 18 Vh. = 2.7 K hf = 220 h ,h re ma y be ne g lected.Ie " e ae

Calcula,te A" , Ri' Ra of the amplifier you have designed.

r-

2. (a) Design an R coupled CS amplifier using FET BW -11 to meet the following 15e -

specification. IA" I> 15 IDSQ=1.2mAFL < 20 Hz.Va = 2.5VRi > 1M ohm.

(b) A certain JFET has IDss= 15 mA and pinch off voltage Vp =- 5 V. 5Calculate value of transconductance for V GS= - 2 V.

3. (a) For full wave rectifier with center tapped transformer (20-0-20 rms, 1550 Hz), Rl =10 Q.

(i) Find Vdc' Ide and ripple factor(ii) Repeat part 1 if 10.000 ~F is considered and is shunted across

the load

(iii) Repeat part 1 if 100 m h inductor is present in series with load.

(b) Draw UJT equivalent circuit and explain UJT characteristic curve. 5

4. (a) Determine RCI ReI RbI Vce and Vb,

~1 ".L V

1} 2. m f.tf2e.~p

f. e..

(4b V

13 :=. g CJ2.,4\1

-

10

(b) (i) Show that in self bias circuit, the drift of quiescent point due 10to temperature changes is made up automatically.

(ii) Compare Triac with Diac.

5. (a) Explain various methods of biasing JFET and MOSFET.

(b) Draw and explain series regulator circuit using BJT.

15

5

[TURN OVER

. "'. - .~

Con. 54~2-RC-8774-08.

6. (a) Find the quiescent values of Vds' Id and Vgs for the amplifier shown. 10I = - 4 mA V =4Vdss P -b 0 V-0

1<6K-£L

2

\(s

.J

R, \.;",.0.

'-I K-fL.

-(b) (i) Explain line regulation and ripple rejection for regulated power 10

supply.

(ii) A particular optocoupler has current transfer ratio of 30 percent. Ifinput current is lOO mA, What is cutput current?

7. (a)

(b)

(c)

(d)

r"\

Describe four ways an 5C5 can be turned off.

Compare methods of biasing BJT.What is critical inductance? What is L section filter?

Explain D-M05FET Amplifier operation.

20

5

",-~

{ (

"P~ max. 1£ max. I,.@25°C @25°C peak pulse currenl max.

300mW SOmA 2Amp.

V.2£VollS max. min. max.

RssKOmin. typo

4.7 7.0

Max.I,.

max. J.lA

5.0

Ivmin. mA

4.0

liD~-2.130

VSZBJVolts

35

T. max1

71UJT type

2N2646 125°C 0.56 0.75 9.1

DBEC DATA SHEET

, Dera'te.

Pdmax Icmax V (..1) Vcso Vc£o VCER VCEX Vs£o' D.C. current gain Small Signal hi' VSI; 0,. aboveC£

'ransislor lype @ 25°C @ 25°C VOIIS vOllS (Sus) (SIlS) VOIIS VOIIS T. max max. °C/W 2SOC

Walls' Amps d.c. d.c. volts d.c. VOllSd.c. d.c. d.c. 1oC min lyp. max. min. typo max. W/oC

:N3055 115.5 15.0 1.1 100 60 70 90 7 200 20 50 70 15 50 120 1.8 \.5 0.7

CN055 50.0 5.0 1.0 60 50 55 60 5 200 25 50 100 25 75 125 1.5 3.5 0-4XNI49 30.0 4.0 1.0 50 40 - - 8 ISO 30 50 \10 33 60 liS 1.2 4.0 0.3XNIOO 5..Q 0'.7 0.6 70 60 65 - 6 200 50 90 280 50 ,90 280 0.9 351C147A 0.25 i(H 0.25 50 4S SO - 6 12S 115 180 220 125 220 260 0.9NS2S(PNP ) 0.225 .5 '0.25 85 30 - - - 100 3S - 65 - 45 - -

rJC147B ().25 -0.1 0.25 50 45 50 - 6 125 200 290 450 240 330 500 0.9

BFW II-JFET MUTUALCHARACTERISTICSTransistor lype hie hoe hre oja

BC 147A 2.7 K 0 18J,lU 1.5 X 10-4 0.4°C/mw2N 525 (PNP) 1.4 K 0 2SJ,lU 3.2 x 10"" --

BC 147B 4.5 K 0 30J,l U 2 x I0-4 0.4°C/mw

-VGSvolts 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.6 2.0 2-4 2.5 3.0 3.5 4.0

IDS,max. mA 10 9.0 8.3 7.6 6.8 6.1 5.4 4.2 3.1 . 2.2 2.0 1.1 0.5 0.0

IDStypo mA 7.0 6.0 5.4 4.6 4.0 3.3 2.7 1.7 0.8 0.2 0.0 0.0 0.0 0.0

IDSmin. mA 4.0 3.0 2.2 1.6 1.0 0.5 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

N-Channel JFET

Type vos max. VDCmax. Vcs max. P max. TJ max. IDSS g",.. -v,. VOIIS rtl Derale 8.Itl

VOIIS Volts VOlls @25°C above 25°C

2N3822 SO SO 50 300 mW 175°C 2 mA 3000 n 6 50 KG 2 mwrc 0.59°C/mW-

BFW 11 (typical) 30 30 30 300 mW 200°C 7 mA 5000 n 2.5 SOKG - 0.59° C/mW