Operational Amplifiers MCQ’s

Analog Electronic Circuits Electronics & Communication Engineering

This set of Analog Electronic Circuits Multiple Choice Questions & Answers (MCQs) focuses on “Operational Amplifiers”.

1. In the given block diagram of an op-amp. What are A, B, C and D?


a) A = Dual input and balanced output differential amplifier, B = Dual input and unbalanced output differential amplifier, C = Level shifter, D = Power amplifier
b) A = Dual input and balanced output differential amplifier, B = Dual input and balanced output differential amplifier, C = Dual input and unbalanced output differential amplifier, D = Normal amplifier
c) A = Dual input and unbalanced output differential amplifier, B = Dual input and balanced output differential amplifier, C = Voltage regulator, D = Power amplifier
d) A = Normal amplifier, B = Dual input and unbalanced output differential amplifier, C = Level shifter, D = Dual input and balanced output differential amplifier

2. In an ideal op-amp, which is not true?
a) Open loop voltage gain is infinite
b) Input resistance is infinite
c) Slew rate is infinite
d) CMRR is zero

3. Which of these is incorrect for an operational amplifier?
a) It has a high voltage gain
b) It is a direct coupled amplifier
c) It is only useful for amplifying AC signals
d) It was originally designed to perform mathematical operations

4. A practical op-amp has a bandwidth of only 10 Hz. Gain is 106, and the required bandwidth is 100 kHz. How much feedback is required?
a) 0.99% negative feedback
b) 0.99% positive feedback
c) 1% negative feedback
d) 1% positive feedback

5. Given that CMRR is 100dB. Input common-mode voltage is 12 V. Differential voltage gain is 4000. Calculate output common-mode voltage.
a) 48V
b) 0.48V
c) 20V
d) 11V

6. Which of the following option is correct according to the below statements?

A: Voltage gain of op-amp decreases at high frequencies
B: Its internal structure uses a capacitor

a) Both A and B are correct, and B is the correct reason for A
b) Both A and B are correct, but B is not the correct reason for A
c) A is correct and B is incorrect
d) A is incorrect and B is correct

7. Given that for an op-amp the gain is 103, the slew rate is 1.5V/μsec. Input is 5×10-3sinωt, calculate maximum frequency to prevent distortion.
a) 47.7 kHz
b) 0.3 MHz
c) 477 Hz
d) 3 kHz

8. The unity gain bandwidth for an op-amp having open loop gain 2×106 is 10 Mhz. Calculate the AC gain of op-amp at an input of 2000 Hz.
a) 2000
b) 5000
c) 10000
d) 12.5

9. Till what frequency do we get amplification from IC 741?
a) Unity gain bandwidth
b) 3-dB frequency
c) Infinity
d) UGB + fOL

10. What is the use of the compensation capacitor in op-amp?
a) Improves the amplification of op-amp
b) Decreases the slew rate of op-amp
c) Increases the bandwidth of op-amp
d) Op-amp acts as all pass filter

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