GlobalEdge Electronics Questions and Answers

 global edge Electronics Based Questions and Answers

1.The breakdown mechanism in a lightly doped p-n junction under reverse biased condition is called
(A) avalanche breakdown.
(B) zener breakdown.
(C) breakdown by tunnelling.
(D) high voltage breakdown.
Ans: A

2.Removing bypass capacitor across the emitter-leg resistor in a CE amplifier causes
(A) increase in current gain. 
(B) decrease in current gain.
(C) increase in voltage gain. 
(D)decrease in voltage gain.
Ans: D

3.When a step-input is given to an op-amp integrator, the output will be
(A) a ramp.
(B) a sinusoidal wave.
(C) a rectangular wave.
(D) a triangular wave with dc bias.
Ans: A

4.Hysteresis is desirable in Schmitt-trigger, because
(A) energy is to be stored/discharged in parasitic capacitances.
(B) effects of temperature would be compensated.
(C) devices in the circuit should be allowed time for saturation and desaturation.
(D) it would prevent noise from causing false triggering.
Ans: C

5.Space charge region around a p-n junction
(A) does not contain mobile carriers
(B) contains both free electrons and holes
(C) contains one type of mobile carriers depending on the level of doping of the p or n
regions
(D) contains electrons only as free carriers
Ans: A

6.The important characteristic of emitter-follower is
(A) high input impedance and high output impedance
(B) high input impedance and low output impedance
(C) low input impedance and low output impedance
(D) low input impedance and high output impedance
Ans: B

7.In a JFET, at pinch-off voltage applied on the gate
(A) the drain current becomes almost zero
(B) the drain current begins to decrease
(C) the drain current is almost at saturation value.
(D) the drain-to-source voltage is close to zero volts.
Ans: C

8.When an amplifier is provided with current series feedback, its
(A) input impedance increases and output impedance decreases
(B) input and output impedances both decrease
(C) input impedance decreases and output impedance increases
(D) input and output impedances both increase
Ans: D

9.The fan-out of a MOS-logic gate is higher than that of TTL gates because of its
(A) low input impedance 
(B) high output impedance
(C) low output impedance 
(D) high input impedance
Ans: D

10.In an intrinsic semiconductor, the Fermi-level is
(A) closer to the valence band
(B) midway between conduction and valence band
(C) closer to the conduction band
(D) within the valence band
Ans: C

11.The common collector amplifier is also known as
(A) collector follower 
(B) Base follower
(C) Emitter follower 
(D) Source follower
Ans: C

12.In an amplifier with negative feedback
(A) only the gain of the amplifier is affected
(B) only the gain and bandwidth of the amplifier are affected
(C) only the input and output impedances are affected
(D) All of the four parameters mentioned above would be affected
Ans: D

13.A differential amplifier, amplifies
(A) and mathematically differentiates the average of the voltages on the two input lines
(B) and differentiates the input waveform on one line when the other line is grounded
(C) the difference of voltages between the two input lines
(D) and differentiates the sum of the two input waveforms
Ans: C

14.It is required to construct a counter to count upto 100(decimal). The minimum number of flipflops
required to construct the counter is
(A) 8 
(B) 7
(C) 6 
(D) 5
Ans: A

15.A highly stable resonance characteristic is the property of a ____ oscillator.
(A) Hartley 
(B) Colpitts
(C) Crystal 
(D) Weinbridge
Ans. (C)

16.The width of depleted region of a PN junction is of the order of a few tenths of a
___________.
(A) millimeter 
(B) micrometer
(C) meter 
(D) nanometer
Ans. (B)

17.In negative feedback the return ratio is __________.
(A) 0 
(B) 1
(C) greater than 0 
(D) greater than 1
Ans. (C)
Ex:In a negative feed back circuit, always the return ratio will be in the range of 0 to 1.

18.A phase shift oscillator uses __________________.
(A) LC tuning 
(B) Piezoelectric crystal
(C) Balanced bridge 
(D) Variable frequency operation
Ans. (C)

19.Transistor is a
(A) Current controlled current device.
(B) Current controlled voltage device.
(C) Voltage controlled current device.
(D) Voltage controlled voltage device.
Ans. (A)
Ex:The output current depends on the input current

20.A bistable multivibrator is a
(A) Free running oscillator. 
(B) Triggered oscillator.
(C) Saw tooth wave generator. 
(D) Crystal oscillator.
Ans. (B)
Ex:The transistors would change their state of operation from ON to OFF and vice versa
depending on the external trigger provided.