Op Amp Objective Type Questions & Answers

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

A 1.273kHz

B 12.73kHz

C 127.3 kHz

D 127.3 Hz

View Answer

Answer: 1.273kHz

22 How many op-amps are required to implement this equation Vo = V1

A 4

B 3

C 2

D 1

View Answer

Answer: 1

23 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

A 10 volts

B 5 volts

C 5/ volts

D 5/2 volts

View Answer

Answer: 5/2 volts

24 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

View Answer

Answer: Voltage controlled Voltage source

25 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

A 50KHz

B 100KHz

C 1000/17KHz

D 1000/7.07KHz

View Answer

Answer: 50KHz

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

A 10 V

B 5 V

C 5V

D 5/2 V

View Answer

Answer: 10 V

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

A Square wave

B Triangular wave

C Parabolic wave

D Sine wave

View Answer

Answer: Sine wave

28 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

A CMMR

B Bandwidth

C Slew rate

D Open-loop gain

View Answer

Answer: Slew rate

29 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

A 23dB

B 25dB

C 46dB

D 50dB

View Answer

Answer: 46dB

30 Differential amplifiers are used in

A Instrumentation amplifiers

B Voltage followers

C Voltage regulators

D Buffers

View Answer

Answer: Instrumentation amplifiers

31 For an ideal op-amp, which of the following is true?

A The differential voltage across the input terminals is zero

B The current into the input terminals is zero

C The current from output terminal is zero

D The output resistance is zero

View Answer

Answer: The current from output terminal is zero

32 The two input terminals of an opamp are labeled as

A High and low

B Positive and negative

C Inverting and non inverting

D Differential ans non differential

View Answer

Answer: Inverting and non inverting

33 For an op-amp having differential gain Av and common-mode gain Ac the CMRR is given by

A Av + Ac

B Av / Ac

C 1 + Av / Ac)

D Ac / Av

View Answer

Answer: Av / Ac

34 Hysteresis is desirable in Schmitt-trigger, because

A Energy is to be stored/discharged in parasitic capacitances

B Effects of temperature would be compensated

C Devices in the circuit should be allowed time for saturation and desaturation

D It would prevent noise from causing false triggering

View Answer

Answer: Devices in the circuit should be allowed time for saturation and desaturation

35 The output voltage Vo of the above circuit is

A -6V

B -5V

C -1.2V

D -0.2V

View Answer

Answer: -5V

36 In differential-mode, …………….

A opposite polarity signals are applied to the inputs

B the gain is one

C the outputs are of different amplitudes

D only one supply voltage is used

View Answer

Answer: opposite polarity signals are applied to the inputs

37 In the common mode, ……………

A both inputs are grounded

B the outputs are connected together

C an identical signal appears on both the inputs

D the output signal are in-phase

View Answer

Answer: an identical signal appears on both the inputs

38 If ADM = 3500 and ACM = 0.35, the CMRR is ……….

A 1225

B 10,000

C 80 dB

D (1) and (3)

View Answer

Answer: (1) and (3)

39 A certain noninverting amplifier has Ri of 1 kO and Rf of 100 kO. The closed-loop voltage gain is ………

A 100,000

B 1000

C 101

D 100

View Answer

Answer: 101

40 A certain inverting amplifier has a closed-loop voltage gain of 25. The Op-amp has an open-loop voltage gain of 100,000. If an Op-amp with an open-loop voltage gain of 200,000 is substituted in the arrangement, the closed-loop gain ……..

A doubles

B drops to 12.5

C remains at 25

D increases slightly

View Answer