# AFCAT: Electronics MCQs (Practice_Test 7 of 13)

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An ideal OP-AMP is an ideal

Current controlled Current source

Current controlled Voltage source

Voltage controlled Voltage source

Voltage controlled Current source

Answer: b

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

50KHz

100KHz

1000/17KHz

1000/7.07KHz

Answer: a

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

795mV

395mV

795mV

39.5mV

Answer: c

The ideal OP-AMP has the following characteristics

Ri = ∞ A = ∞ R0 = 0

Ri = 0, A = ∞ R0 = 0

Ri = ∞ A = ∞ R0 = ∞

Ri = 0, A = ∞ R0 = ∞

Answer: b

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

∞

120k

110k

10k

Answer: c

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

10 V

5 V

5V

5/2 V

Answer: a

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

square wave

Triangular wave

Parabolic wave

Sine wave

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

CMMR

bandwidth

slew rate

open-loop gain

Answer: c

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

2

1

½

0

Answer: c

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

23dB

25dB

46dB

50dB

Answer: b