Competitive Exams: Electronics MCQs (Practice-Test 7 of 13)

  1. 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

    Answer: b

  2. 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

    Answer: a

  3. 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

    Answer: c

  4. The ideal OP-AMP has the following characteristics

    1. Ri = ∞ A = ∞ R0 = 0

    2. Ri = 0, A = ∞ R0 = 0

    3. Ri = ∞ A = ∞ R0 = ∞

    4. Ri = 0, A = ∞ R0 = ∞

    Answer: b

  5. The approximate input impedance of the opamp circuit which has Ri = 10k, Rf = 100k, RL = 10k

    1. 120k

    2. 110k

    3. 10k

    Answer: c

  6. 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

    Answer: a

  7. 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

  8. 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

    Answer: c

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

    1. 2

    2. 1

    3. ½

    4. 0

    Answer: c

  10. 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

    1. 23dB

    2. 25dB

    3. 46dB

    4. 50dB

    Answer: b