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

Code No: 07A3EC14 Set No.1
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
? ? ? ? ?
1. (a) De?ne h-parameter of a transistor in a small signal ampli?er. elaborate the
bene?ts of h-parameters?
(b) In a typical single stage CE ampli?er, Rs=1kO, RL=1.2kO using hfe=50,
hoe=25×10-6
A/V, hre=2.5×10-4
, hie=1100O. obtain AI , AV , Z1 and Zo. [8+8]
2. (a) Draw and discuss the 2 stage ampli?er with Darlington connection. provide
the advantages of this circuit.
(b) An ampli?er consists of three identical stages in cascade. The bandwidth of overall
ampli?er extends from 20 Hz to 20 kHz. compute the bandwidth of individual
stage. [8+8]
3. (a) Draw the hybrid-p equivalent of a CE transistor valid for high frequency and
discuss signi?cance of every parameters.
(b) At IC=1mA and VCE=10V, a certain transistor data indicates CC= Cb0
C=3PF,
hfe=200 and ?T=-500 Mrad/sec. compute gm, ?b0
e, Ce,=Cb0
e and Wß. [8+8]
4. (a) discuss the classi?cation of power ampli?ers based on class of operation and
compare them.
(b) A power ampli?er supplies 3w to a load of 6KO. The zero signal d.c collector
current in 55 mA and the collector current with signal in 60mA. How much is
the percentage in 2nd harmonic distortion? [8+8]
5. (a) Draw and discuss the circuit diagram of single tuned inductively coupled am-
pli?er using BJT?
(b) Draw its HF circuit and discuss it. [8+8]
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=500PF, L=20µH, RL=1.5K and the transistor
has hfe=50 and input resistance of 200 O. The coil used has Q factor=30.
Calculate
i. resonant frequency of the tuned circuit
ii. impedance of the tuned circuit
iii. Voltage gain of the stage. [8+8]
7. (a) discuss the operation of simple zener skunt voltage regulator.
1 of 2Code No: 07A3EC14 Set No.1
(b) The zener diode used in the shunt voltage regulator circuit has a breakdown
of voltage of 10V. The series current limiting resistance is 200 O. compute
the un regulated d.c input voltage when the zever current in 15mA and the
load current is 50mA. If now the input voltage modifications to 30V, compute the
new zener current, assuming constant load. [8+8]
8. (a) discuss the principal of IC 723 voltage regulator.

Earning:   Approval pending.