16-02-2013, 03:07 PM
OBJECTIVE QUESTIONS IN ANALOG ELECTRONICS
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1. The early effect in a bipolar junction transistor is caused by
(a) fast turn-on (b)fast turn-off
© large collector-base reverse bias (d) large emitter-base forward bias
2. MOSFET can be used as a
(a) current controlled capacitor (b) voltage controlled capacitor
© current controlled inductor (d) voltage controlled inductors
3. Thermal runaway is not possible in FET because as the temperature of FET increases
(a) the mobility decreases (b) the transconductance increases
© the drain current increases (d) none of the above
4. A source follower using an FET usually has a voltage gain which is
(a) greater than +100 (b) slightly less than unity but positive
© exactly unity but negative (d) about -10
5. A differential amplifier has a differential gain of 20,000 . CMRR=80 dB. The common mode
gain is given by
(a) 2 (b) 1 © ½ (d) 0
6. The approximate input impedance of the OPAMP circuit which has
Ri=10k,Rf=100k,RL=10k
(a) ∞ (b)120k ©110k (d)10k
7. An OPAMP has a slew rate of 5 V/μ S .The largest sine wave O/P voltage possible at a
frequency of 1MHZ is
(a) 10 volts (b) 5 volts © 5/ volts (d)5/2 volts
8. A change in the value of the emitter resistance Re in a differential amplifier
(a) affects the difference mode gain Ad (b) affects the common mode gain Ac
©affects both Ad and Ac (d) does not effect either Ad and Ac
9. A differential amplifier is invariably used in the i/p stage of all OP-AMPs.This is dome
basically to provide the OP-AMPs with a very high
(a)CMRR (b)bandwidth © slew rate (d)open-loop gain
10. The effective channel length of a MOSFET in a saturation decreases with increase in
(a) gate voltage (b)drain voltage ©source voltage (d)body voltage
11. Which of the following is not associated with a p-n junction
(a) junction capacitance (b)charge storage capacitance
©depletion capacitance (d)channel length modulation
12. In a p-n junction diode under reverse bias, the magnitude of electric field is maximum at
(a) the edge of the depletion region on the p-side
(b) the edge of the depletion region on the n-side
© the p-n junction
(d) the center of the depletion region on the n-side
13. An n- channel JFET has IDSS=2mA,and Vp=-4v.Its transconductance gm=(in mA/V)for an
applied gate to source voltage VGS=-2v is
(a)0.25 (b)0.5 ©0.75 (d)1
14. In a common emitter, unbypassed resister provides
(a)voltage shunt feedback (b)current series feedback
©negative voltage feedback (d)positive current feedback
15. A constant current signal across a parallel RLC circuits gives an o/p of 1.4v at the signal
frequency of 3.89KHZ and 4.1KHZ .At the frequency of 4KHZ,the o/p voltage will be
(a)1 v (b) 2v ©1.4v (d)2.8v
16. Class AB operation is often used in power (large signal) amplifiers in order to
(a) get maximum efficiency (b)remove even harmonics
© overcome a crossover distortion (d)reducing collector dissipation
17. The bandwidth of an RF tuned amplifier is dependent on
(a) Q –factor of the tuned o/p circuit
(b) Q –factor of the tuned i/p circuit
© Quiescent operating point
(d) Q-factor of the o/p and i/p circuits as well as quiescent operating point
18. If =0.98 ,Ico=6μA and Iβ=100μA for a transistor,then the value of Ic will be
(a)2.3mA (b)3.2mA ©4.6 mA (d)5.2mA
19.The MOSFET switch in its on-state may be considered equivalent to
(a)resistor (b)inductor ©capacitor (d)battery
20. Most of the linear ICs are based on the two-transistor differential amplifier because of its
(a) input voltage dependent linear transfer characteristic
(b) high voltage gain
© high input resistance
(d) high CMRR
21. Negative feedback in an amplifier
a) Reduces gain
b) Increase frequency &phase distortion
c) Reduces bandwidth
d) Increases noise