Opamp Circuits

1. A 741-Type OP-AMP has a gain-bandwith product of 1MHz. A non-inverting amplifier using this opamp & having a voltage gain of 20db will exhibit -3db bandwidth of

  1. 50KHz
  2. 100KHz
  3. 1000/17KHz
  4. 1000/7.07KHz

Correct answer: (A)

2. A differential amplifier has a differential gain of 20,000. CMMR=80dB. The common mode gain is given by

  1. 2
  2. 1
  3. 43862
  4. 0

Correct answer: (A)

3. 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

  1. CMMR
  2. Bandwidth
  3. Slew rate
  4. Open-loop gain

Correct answer: (C)
Slew rate

4. A non inverting closed loop op amp circuit generally has a gain factor

  1. Less than one
  2. Greater than one
  3. Of zero
  4. Equal to one

Correct answer: (B)
Greater than one

5. 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 20KHz without introducing any slew-rate induced distortion, then the input signal level exceed

  1. 795mV
  2. 395mV
  3. 795mV
  4. 39.5mV

Correct answer: (C)

6. An ideal OP-AMP is an ideal

  1. Current controlled Current source
  2. Current controlled voltage source
  3. Voltage controlled voltage source
  4. voltage controlled current source

Correct answer: (C)
Voltage controlled voltage source

7. An OPAMP has a slew rate of 5 V/μ S .The largest sine wave O/P voltage possible at a frequency of 1 MHZ is

  1. 10 volts
  2. 5 volts
  3. 5/ volts
  4. 5/2 volts

Correct answer: (D)
5/2 volts

8. An opamp has a slew rate of 5V/ S. the largest sine wave o/p voltage possible at a frequency of 1MHz is

  1. 10 V
  2. 5 V
  3. 5V
  4. 5/2 V

Correct answer: (A)
10 V

9. Assume that the op-amp of the fig. is ideal. If Vi is a triangular wave, then V0 will be

  1. Square wave
  2. Triangular wave
  3. Parabolic wave
  4. Sine wave

Correct answer: (D)
Sine wave

10. Calculate the cutoff frequency of a first-order low-pass filter for R1 = 2.5kΩ and C1 = 0.05μF

  1. 1.273kHz
  2. 12.73kHz
  3. 127.3 kHz
  4. 127.3 Hz

Correct answer: (A)

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