# Op Amp MCQs | Op Amp Multiple Choice Questions(MCQs) & Answers

Questions
1 A differential amplifier ……………..
A is a part of an Op-amp
B has one input and one output
C has two outputs

2 When a differential amplifier is operated single-ended, …………
A the output is grounded
B one input is grounded and signal is applied to the other
C both inputs are connected together
D the output is not inverted

Answer: one input is grounded and signal is applied to the other
3 The common-mode gain is ………..
A very high
B very low
C always unity
D unpredictable

4 If ADM = 3500 and ACM = 0.35, the CMRR is ……….
A 1225
B 10,000
C 80 dB

5 Of the values listed, the most realistic value for open-loop voltage gain of an OP-amp is ……
A 1
B 2000
C 80 dB
D 100,000

6 The output of a particular Op-amp increases 8V in 12μs. The slew rate is …….
A 90 V/μs
B 0.67 V/μs
C 1.5 V/μs
D none of these

7 For an Op-amp with negative feedback, the output is …….
A equal to the input
B increased
C fed back to the inverting input
D fed back to the noninverting input

Answer: fed back to the inverting input
8 Negative feedback ………..
A increases the input and output impedances
B increases the input impedance and bandwidth
C decreases the output impedance and bandwidth
D does not affect impedance or bandwidth

Answer: increases the input impedance and bandwidth
9 If the feedback resistor in Q15 (above question) is open, the voltage gain …….
A increases
B decreases
C is not affected
D depends on Ri

10 A voltage follower ……….
A has a voltage gain of 1
B is noninverting
C has no feedback resistor
D has all of these

11 The input offset current equals the ……….
A difference between two base currents
B average of two base currents
C collector current divided by current gain
D none of these

Answer: difference between two base currents
12 The node voltage at the top of the til resistor is closes to ……….
A collector supply voltage
B zero
C emitter supply voltage
D tail current times base resistance

13 The tail current in a differential amplifier equals …….
A difference between two emitter currents
B sum of two emitter currents
C collector current divided by current gain
D collector voltage divided by collector resistance

Answer: sum of two emitter currents
14 The input impedance of a differential amplifier equals r’e times ……
A β
B RE
C RC
D

15 The common-mode voltage gain is ………
A smaller than differentail voltage gain
B equal to differential voltage gain
C greater than differential voltage gain
D none of the above

Answer: smaller than differentail voltage gain
16 The input stage of an Op-amp is usually a ……….
A differential amplifier
B class B push-pull amplifier
C CE amplifier
D swamped amplifier

17 Current cannot flow to ground through …….
A a mechanical ground
B an a.c. ground
C a virtual ground
D an ordinary ground

18 A non inverting closed loop op amp circuit generally has a gain factor
A Less than one
B Greater than one
C Of zero
D Equal to one

19 An ideal OP-AMP is an ideal
A Current controlled Current source
B Current controlled voltage source
C Voltage controlled voltage source
D voltage controlled current source