West Bengal Institute of Technology (WBIT) 2011-4th Sem B.Tech Electronics and Communications Engineering B-TECH ANALOG ELECTRONIC CIRCUITS,,ESTER,WBUT - Question Paper

GROUP-A
( Multiple option kind answer)

1. select the accurate options for any ten of the following: 10*1=10

i) The early effect in a bipolar junction transistor is caused by
a) fast turn-on
b) fast turn-off
c) large collector-base reverse bias
d) large emitter-base forward bias
ii) MOSFET can be used as a
a) current controlled capacitor
b) voltage controlled capacitor
c) current controlled inductor
d) voltage controlled inductor
iii) Thermal runaway is not possible in FET because as the temperature of FET increases
a) the mobility reduces
b) the transconductance increases
c) the drain current increases
d) none of these
iv) A differential amplifier has a differential gain of 20000. CMRR=80 dB. The common mode gain is provided by
a) 2
b) 1
c) 1/2
d) 0.
v) Negative feedback in an amplifier
a) decreases gain
b) increases frequency and phase distortion
c) decreases bandwidth
d) increases noise.
vi) The zero crossing detector is 1 application of a/an
a) differentiator
b) integrator
C) summing amplifier
d) comparator.
vii) A Wien- bridge oscillator has frequency
a) 1/{2pi sqrt(RC)}
b) 1/sqrt(RC)
c) 1/{2piRC}
d) none of these
viii) An RC phase oscillator will not produce any oscillation until and unless the voltage gain of its internal amplifier is
a) unity
b) less then unity
c) around 3
d) more than 29.
ix) The kind of power amplifier which exhibits cross-over distortion in its output is
a) Class A
b) Class B
c) Class AB
d) Class C.
x) Which of the subsequent oscillators is used as an audio frequency?
a) Crystal oscillator
b) Wien-bridge oscillator
c) RC-phase shift oscillator
d) Colpitts oscillator.
xi) A non-inverting Op-amp summer is shown beneath in figure provided beneath. the output voltage V0 is

a) 3/2 sin wt
b) 3sin wt
c) two sin wt
d) none of these.
xii) In series voltage regulator series pass transistor is
a) an emitter follower
b) a voltage follower
c) a comparator
d) none of these.
xiii) The output impedance of a shunt series feedback amplifier is
a) R0/(1+ßA)
b) R0(1+ßA)
c) ßRo/(1+A)
d) none of these.
xiv) In case of monostable operation the formula for the pulse width is provided by

Earning:   Approval pending.