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analog electronics MCQs

Practise focused analog electronics questions with marked answers for exam preparation and subject revision.

analog electronics Mcqs
1. In a CB amplifier the maximum efficiency could be____________?
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A. 99%

B. 25%

C. 50%

D. 85%

2. In a p-n junction diode under reverse bias , the magnitude of electric field is maximum at_____________?
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A. the edge of the depletion region on the p-side

B. the center of the depletion region on the n-side

C. the p-n junction

D. the edge of the depletion region on the n-side

3. The most commonly used amplifier in sample & hold circuits is______________?
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A. A unity gain non-inverting amplifier

B. An inverting amplifiers with a gain of 100

C. A unity gain inverting amplifier

D. An inverting amplifier with a gain of 10

4. A dc power supply has no-load voltage of 30v,and a full-load voltage of 25v at full-load current of 1A.Its output resistance & load regulation ,respectively are_____________?
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A. 25 ? & 20 %

B. 5 ? & 20 %

C. 25 ? & 16.7 %

D. 5 ? & 16.7 %

5. An amplifier without feedback has a voltage gain of 50,input resistance os 1 K? & Output resistance of 2.5K?.The input resistance of the current-shunt negative feedback amplifier using the above amplifier with a feedback factor of 0.2 is___________?
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A. 1/11K?

B. 11K?

C. 1/5K?

D. 5K?

6. The effective channel length of a MOSFET in a saturation decreases with increase in___________?
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A. Source voltage

B. Body voltage

C. Gate voltage

D. Drain voltage
7. In a full-wave rectifier using two ideal diodes,Vdc & Vm are the dc & peak values of the voltage respectively across a resistive load. If PIV is the peak inverse voltage of the diode, then the appropriate relationships for this rectifier is____________?
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A. Vdc = 2Vm/?, PIV=2vm

B. Vdc = 2Vm/?, PIV=Vm

C. Vdc = Vm/?, PIV=Vm

D. Vdc = Vm/?, PIV=2Vm

8. Voltage Series feedback also called series-shunt feedback) results in__________?
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A. Increase in both input & output impedances

B. Decreases in both input & output impedances

C. Increase in input impedance & decreases in output impedance

D. Decrease in input impedance & increase in output impedance

9. The current gain of a bipolar transistor drops at high frequencies because of____________?
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A. High current effects in the base

B. The early effect

C. Transistor capacitances

D. Parasitic inductive elements

10. Which of the following amplifier circuit using junction transistor has the best gain?
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A. Common base

B. Common collector

C. All have the same gain

D. Common emitter
11. A differential amplifier has a differential gain of 20,000 . CMRR=80 dB. The common mode gain is given by________?
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A. 2-Jan

B. 1

C. 2

D. 0

12. A source follower using an FET usually has a voltage gain which is___________?
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A. greater than +100

B. about -10

C. slightly less than unity but positive

D. exactly unity but negative

13. The cascade amplifier is a multistage configuration of__________?
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A. CE-CB

B. CB-CC

C. CE-CC

D. CC-CB .

14. In an op-amp differentiator:________________?
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A. the amplitude of output is proportional to rate of change of input

B. polarity of input and output is the same

C. output occurs when input is finite and constant

D. the amplitude of output is proportional to input

15. A change in the value of the emitter resistance Re in a differential amplifier?
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A. affects the difference mode gain Ad

B. affects the common mode gain Ac

C. ffects both Ad and Ac

D. does not effect either Ad and Ac

16. The action of JFET in its equivalent circuit can best be represented as a_____________?
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A. voltage controlled current source

B. Current controlled voltage source

C. Current controlled Current source

D. Voltage controlled voltage source

17. Most of the linear ICs are based on the two-transistor differential amplifier because of its___________?
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A. high input resistance

B. high voltage gain

C. high CMRR

D. input voltage dependent linear transfer characteristic

18. The early effect in a bipolar junction transistor is caused by_______________?
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A. fast turn-off

B. large emitter-base forward bias

C. large collector-base reverse bias

D. fast turn-on

19. The current gain of a BJT is__________?
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A. gm r?

B. gm /r?

C. gm r0

D. gm / r0

20. A differential amplifier is invariably used in the i/p stage of all OP-amps. This is done basically to provide the OP-amps with a very high_________?
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A. Open-loop gain

B. Slew rate

C. CMMR

D. Bandwidth

21. An OPAMP has a slew rate of 5 V/? S .The largest sine wave O/P voltage possible at a frequency of 1 MHZ is [Hint: Slew rate is defined as the max. rate of change of output voltage. Its unit is V/?S.
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A. 10 volts

B. 5/2 volts

C. 5/1 volts

D. 5 volts

22. In a common emitter, unbypassed resister provides___________?
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A. voltage shunt feedback

B. current series feedback

C. positive current feedback

D. negative voltage feedback
23. In all base driver amplifiers__________?
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A. ac collector voltage is 180 out of phase with ac base voltage

B. none of the above

C. ac emitter voltage is 180 out of phase with ac base voltage

D. ac collector voltage is in phase with ac base voltage

24. The MOSFET switch in its on-state may be considered equivalent to_____________?
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A. capacitor

B. battery

C. inductor

D. resistor

25. . If =0.98 ,Ico=6A and I?=100A for a transistor,then the value of Ic will be______?
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A. 4.6 mA

B. 3.2mA

C. 2.3mA

D. 5.2mA
26. 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___________?
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A. 0.25

B. 1

C. 0.75

D. 0.5
27. Generally, the gain of a transistor amplifier falls at high frequencies due to the___________?
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A. Coupling capacitor at the input

B. Skin effect

C. Coupling capacitor at the output

D. Internal Capacitance of the device
28. Class AB operation is often used in power large signal amplifiers in order to_________?
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A. remove even harmonics

B. get maximum efficiency

C. overcome a crossover distortion

D. reducing collector dissipation

29. An npn BJT has gm=38mA/v, c =1014 F, c? =1013F and DC current gain ?0=90.For this transistor fT & f? are________?
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A. fT =1.47 x 1010 Hz & f? = 1.33 x 1012 Hz

B. fT =1.64 x 108 Hz & f? = 1.47 x 1010 Hz.

C. fT =1.33 x 1012 Hz & f? = 1.47 x 1010 Hz

D. fT =1.47 x 1010 Hz & f? = 1.64 x 108 Hz
30. The bandwidth of an RF tuned amplifier is dependent on____________?
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A. Quiescent operating point

B. Q factor of the tuned i/p circuit

C. Q factor of the tuned o/p circuit

D. Q-factor of the o/p and i/p circuits as well as quiescent operating point

31. The horizontal intercept of dc load line is the same as ideal____________?
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A. saturation point

B. quasi saturation point

C. operating point

D. cut off point
32. MOSFET can be used as a__________?
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A. voltage controlled capacitor

B. voltage controlled inductors

C. current controlled capacitor

D. current controlled inductor

33. Three identical amplifiers with each one having a voltage gain of 50,input resistance of 1K? & output resistance of 250 ,are cascaded.The open circuit voltage gain of combined amplifier is_________?
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A. 102dB

B. 98dB

C. 51dB

D. 49dB

34. 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___________?
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A. 2v

B. 1 v

C. 2.8v

D. 1.4v

35. The encapsulation of transistor is necessary for__________?
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A. preventing photo-emission effects

B. mechanical ruggedness

C. avoiding loss of free electrons

D. preventing radio interference

36. A 741-type OP-AMP has a gain-bandwidth product of 1MHz. A non-inverting amplifier using this op-amp & having a voltage gain of 20db will exhibit -3db bandwidth of__________?
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A. 50 KHz

B. 100KHz

C. 1000/7.07 KHz

D. 1000/17 KHz

37. In the differential voltage gain & the common mode voltage gain of a differential amplifier are 48db &2db respectively, then its common mode rejection ratio is__________?
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A. 46dB

B. 50dB

C. 23dB

D. 25dB

38. In deriving ac equivalent circuit for an amplifier circuit, we short circuit___________?
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A. all transistors

B. all inductors

C. all resistors

D. all capacitors
39. To prevent a DC return between source and load, it is necessary to use___________?
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A. capacitor between source and load

B. either A. or B.

C. resistor between source and load

D. inductor between source and load

40. Introducing a resistor in the emitter of a common amplifier stabilizes the dc operating point against variations in____________?
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A. Only the temperature

B. only the ? of the transistor

C. Both Temperature & ?

D. None of the above

41. In a transistor leakage current mainly depends on__________?
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A. size of emitter

B. temperature

C. doping of base

D. rating of transistor

42. Negative feedback in an amplifier____________?
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A. Increases noise

B. Reduces gain

C. Increase frequency &phase distortion

D. Reduces bandwidth

43. When a transistor is connected in common emitter mode, it with have__________?
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A. negligible input resistance and high output resistance

B. low input resistance as well as output resistance

C. medium input resistance and high output resistance

D. high input resistance and low output resistance

44. An amplifier using an opamp with slew rate SR=1v/sec has a gain of 40db.if this amplifier has to faithfully amplify sinusoidal signals from dc to 20 KHz without introducing any slew-rate induced distortion, then the input signal level must not exceed________?
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A. 795 mV

B. 795mV

C. 39.5mV

D. 395mV

45. An ideal OP-AMP is an ideal___________?
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A. voltage controlled current source

B. Current controlled Current source

C. Current controlled voltage source

D. Voltage controlled voltage source

46. Which of the following is not associated with a p-n junction?
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A. junction capacitance

B. depletion capacitance

C. channel length modulation

D. charge storage capacitance

47. Thermal runaway is not possible in FET because as the temperature of FET increases_________________?
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A. the transconductance increases

B. the drain current increases

C. the mobility decreases

D. none of the above