1. A Colpitt’s oscillator uses _____.

Answers:

  1. a tapped inductor
  2. a tapped capacitor
  3. no tapped inductor or capacitor
  4. both a tapped inductor and a tapped capacitor

2. A Wien-bridge oscillator is basically a _____.

Answers:

  1. pulse generator
  2. sine-wave generator
  3. square-wave generator
  4. triangular wave generator

3. A voltage V=300cos100t is applied to a half wave rectifier with RL =5KΩ. The rectifier may be represented by an ideal diode in series with a resistance of 1KΩ. What would be the ripple factor in this case?

Answers:

  1. 0
  2. 100%
  3. 110.21%
  4. 121.13%

4. A bridge rectifier circuit has secondary voltage of 12Vr.m.s. Assume secondary resistance and diode forward resistance to be negligible. The load resistance is 100Ω. What would be the peak load current?

Answers:

  1. 0.169 Amp
  2. 0.108 Amp
  3. 0.118 Amp
  4. 11.8 Amp

5. A half wave rectifier supplies power to 1000Ω load from a 110V (r.m.s) source of supply. If the forward resistance of the diode is 20Ω. What would be the efficiency of the rectifier?

Answers:

  1. 50%
  2. 25.73%
  3. 39.73%
  4. 30.11%

6. After triggering an SCR , the gate pulse is removed. the current in the SCR will _____.

Answers:

  1. remain the same
  2. immediately fall to zero
  3. rise-up
  4. rise a little and fall to zero

7. A feedback amplifier has an internal gain = 40dB and a feedback factor = 0.05, if the input impedance of this circuit is 12KΩ. What would have been the input impedance of the amplifier if the feedback had not been present?

Answers:

  1. 1KΩ
  2. 2KΩ
  3. 3KΩ
  4. 4KΩ

8. An amplifier has a gain of 10 without feedback. To make it oscillate, ß must be _____.

Answers:

  1. 0.2
  2. 0.1
  3. 0.5
  4. 0.8

9. For designing a Push-Pull amplifier, the type of transistors should be _____.

Answers:

  1. one should be p-n-p and the other should be n-p-n
  2. Both should be either p-n-p or n-p-n
  3. both should be n-p-n only
  4. All of the above

10. A crystal oscillator provides very stable frequency because of _____.

Answers:

  1. the high stability of the crystal
  2. the rigid crystal structure
  3. the low XL/R ratio of the crystal
  4. the high Q of the crystal

11. A transistor is a semiconductor switch which is _____.

Answers:

  1. unilateral and astable
  2. bilateral and astable
  3. unilateral and bistable
  4. bilateral and bistable

12. An Emitter follower is used for _____.

Answers:

  1. high current gain
  2. high voltage gain
  3. impedance matching
  4. high power gain

13. An amplifier has a bandwidth of 200KHz and a voltage gain of 100. What will be the new bandwidth if 5% negative feedback is introduced?

Answers:

  1. 1000KHz
  2. 1200KHz
  3. 1600KHz
  4. 2000KHz

14. A differentiator converts a linear ramp into a _____.

Answers:

  1. triangular wave
  2. square wave
  3. sinusoidal wave
  4. constant D.C signal

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