Jawaharlal Nehru Technological University Kakinada 2008 B.Tech Electronics and Communications Engineering electronic circuit analysis - Question Paper

4. (a) Draw a neat circuit diagram of pushpull class B ampli?er. discuss its working.
(b) In a class B complementary power ampli?er Vcc=+15V, -Vcc=15V and RL=4O.
Calculate
i. maximum a.c power which can be developed
1 of 2Code No: 07A3EC14 Set No.3
Figure 3:
ii. collector dissipation while developing maximum a.c power
iii. e?ciency
iv. maximum power dissipation per transistor. [8+8]
5. Draw the HF equivalent circuit of a single tuned capacitine coupled BJT ampli?er
and derive the expression for
(a) voltage gain
(b) voltage gain at resonance
(c) three dB bandwidth. [16]
6. (a) discuss the concept of staggered tuned ampli?er with the help of frequency
response.
(b) A single tuned transistor ampli?er is used to ampli?er modulated RF carrier
of 500 KHz and bandwidth of 20KHz. The circuit has a total output resistance
Rt=40KO and output capacitance Co=50PF. Calcualte values of inductance
and capacitance of the tuned circuit. [8+8]
7. (a) Draw a neat circuit of transistor shunt regulator and discuss its principle.
(b) A simple zener diode regulator uses a 12V zener diode with series resistance
of 100 O. The unregulated Supply is 15V. Determine:
i. the necessary power rating of the zener.
ii. the highest load current that can be supplied with the diode if Rz is 10O
and Izmin=5mA. [8+8]
8. (a) What in catcher diode and discuss the necessity of catcher diode in switch
regulator with the help of circuit diagram.
(b) List the operating ratings and electrical characteristics of IC 723. [8+8]
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2 of 2Code No: 07A3EC14 Set No.4
II B.Tech. I Semester Regular Examinations, November -2008
ELECTRONIC CIRCUIT ANALYSIS
( Common to Electronics & Communication Engineering and Electronics &
Telematics)
Time: three hours Max Marks: 80
ans any 5 ques.
All ques. carry equal marks
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1. (a) elaborate h-paraneters? Why they called so? De?ne them and elaborate the
bene?ts of h-parameters.
(b) In a single stage CE ampli?er with un bypassed emitter resistance, Rs=1KO,
R1=50, R2=2K, RC=1K, RE=270, and RL=1.2KO. obtain AI , AV , Ri and Ro.
The h-parameters provided are hie=1100, hfe=50. [8+8]
2. (a) Compare the 4 kinds of coupling methods used in multistage ampli?ers.
(b) For the circuit shown in ?gure 4, compute Ri, Ai, Av and Ro for hie=1KO,
hfe=50,hre=2×10-4
, hoe=20µA/V. [8+8]
Figure 4:
3. (a) De?ne fa fß and fT and Derive the relation ranging from fß and fT
(b) A HF ampli?er uses a transistor which is driven from a source with Rs=1K.
compute value of fH, ia, RL=0 and RL = 2KO. Typical values for hybrid-p
parameters are: rb0
e = 1K, ?bb0 = 100O, Ce = 100PF, CC = 3PF and gm =
50mA/V. [8+8]
4. (a) Prove that the maximum e?ciency of a class B ampli?er in 78.5%
(b) A series fed class A ampli?er uses a supply voltage of 10V and load resistance
of 20O. The a.c input voltage outcomes in a base current of 4mA peak. compute
i. d.c input power
ii. a.c output power
1 of 2Code No: 07A3EC14 Set No.4
iii. %e?ciency. [8+8]
5. Draw the HF equivalent circuit of a Tapped single tuned capacitance coupled am-
pli?er using BJT and derive the expressions for
(a) voltage gain
(b) voltage gain at resonance. [16]
6. (a) Draw the circuit diagram of BJT tuned class B/C ampli?er and brie?y discuss
its working. elaborate the applications of tuned ampli?ers?
(b) In a tuned ampli?er circuit C=400PF, L=30µH RL=1.5K and the transistor
has hfe=60 and input resistance of 200O. The coil used has Q factor = 30.
Calculate
i. fr of the tuned circuit
ii. impedance of the tuned circuit
iii. voltage gain of the stage. [8+8]
7. (a) discuss the principle of simple series regulator circuit using transistor.
(b) For the shunt regulator shown in ?gure 5, determine the output voltage and
the circuit currents. [8+8]
Figure 5:
8. (a) Draw the diagram of IC 723 voltage regulator and discuss its principle.
(b) With a neat circuit discuss the working of voltage multiplier. elaborate its
applications. [8+8]
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Earning:   Approval pending.