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# Operational Amplifiers - MCQ Test

## 20 Questions MCQ Test Mock Test Series for Electrical Engineering (EE) GATE 2020 | Operational Amplifiers - MCQ Test

Description
This mock test of Operational Amplifiers - MCQ Test for Railways helps you for every Railways entrance exam. This contains 20 Multiple Choice Questions for Railways Operational Amplifiers - MCQ Test (mcq) to study with solutions a complete question bank. The solved questions answers in this Operational Amplifiers - MCQ Test quiz give you a good mix of easy questions and tough questions. Railways students definitely take this Operational Amplifiers - MCQ Test exercise for a better result in the exam. You can find other Operational Amplifiers - MCQ Test extra questions, long questions & short questions for Railways on EduRev as well by searching above.
QUESTION: 1

### For the circuit shown in fig. the input resistance is Solution:

Since op-amp is ideal  QUESTION: 2

### In the circuit of fig. the op-amp slew rate is SR = 0.5 V/μs. If the amplitude of input signal is 0.02 V, then the maximum frequency that may be used is Solution:  QUESTION: 3

### In the circuit of fig. the input offset voltage and input offset current are Vio = 4 mV and Iio = 150 nA. The total output offset voltage is Solution:  QUESTION: 4

io = ? Solution:  QUESTION: 5

Consider the circuit shown below Que: If vi =2 V, then output vo is

Solution:

If vi > 0, then v0 < 0, D1 blocks and D2 conducts QUESTION: 6

Consider the circuit shown below Que: If vi = -2 V, then output vo is

Solution:

If vi < 0, then v0 > 0, D1 blocks and D2 conducts QUESTION: 7 Solution:

Voltage follower v0 = v = v+ QUESTION: 8

The circuit shown in fig. is at steady state before the switch opens at t = 0. The vc(t) for t > 0 is Solution: For t > 0 the equivalent circuit is shown in fig. QUESTION: 9

The LED in the circuit of fig. will be on if vis Solution: When v+ > 5 V, output will be positive and LED will be on. Hence (C) is correct.

QUESTION: 10

In the circuit of fig. the CMRR of the op-amp is 60 dB. The magnitude of the vo is Solution:  QUESTION: 11

The analog multiplier X of fig. has the characteristics vp = v1v2 The output of this circuit is Solution:

v+ = 0 = v- QUESTION: 12

If the input to the ideal comparator shown in fig. is a sinusoidal signal of 8 V (peak to peak) without any DC component, then the output of the comparator has a duty cycle of Solution:

When vi > 2 V, output is positive. When vi < 2 V, output is negative.  QUESTION: 13

In the op-amp circuit given in fig. the load current iL is Solution:  QUESTION: 14

In the circuit of fig. output voltage is |vo| =1 V for a certain set of ω, R, an C. The |vo| will be 2 V if Solution:

This is a all pass circuit Thus when ω and R is changed, the transfer function is unchanged

QUESTION: 15

In the circuit of fig. the 3 dB cutoff frequency is Solution:  QUESTION: 16

The phase shift oscillator of fig. operate at f = 80 kHz. The value of resistance RF is Solution:

The oscillation frequency is QUESTION: 17

The value of C required for sinusoidal oscillation of frequency 1 kHz in the circuit of fig. is Solution:

This is Wien-bridge oscillator. The ratio is greater than 2. So there will be
oscillation  QUESTION: 18

In the circuit shown in fig. the op-amp is ideal. If βF = 60, then the total current supplied by the 15 V source is Solution:

v+ = 5V = v = VE ,

The input current to the op-amp is zero. QUESTION: 19

In the circuit in fig. both transistor Q1 and Q2 are identical. The output voltage at T = 300 K is Solution:  QUESTION: 20

In the op-amp series regulator circuit of fig. Vz = 62. V, VBE = 0.7 V and β = 60. The output voltage vo is Solution:  