OP Amp MCQ Questions & Answers | Electrical Engineering

31

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.

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Answer & Solution

Answer: Option C

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32

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

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Answer & Solution

Answer: Option B

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33

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

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Answer & Solution

Answer: Option C

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34

The differential voltage gain of a differential amplifier is equal to RC divided by

A) r'_e B) $$\frac{{{\text{r}}{{\text{'}}_{\text{e}}}}}{2}$$ C) 2r'_e D) R_E

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Answer & Solution

Answer: Option C

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35

How many OP-amps are required to implement this equation

A) 2 B) 3 C) 4 D) 1

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Answer & Solution

Answer: Option D

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36

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

A) 100000 B) 1000 C) 101 D) 100

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Answer & Solution

Answer: Option C

Solution:

To find the closed-loop voltage gain of a noninverting amplifier, use the formula:

Closed-loop voltage gain $$A_{v}$$ = $$1 + \frac{R_f}{R_i}$$

Given:
- $$R_i$$ (input resistance) = 1 kΩ
- $$R_f$$ (feedback resistance) = 100 kΩ

Substitute these values into the formula:

$$A_{v} = 1 + \frac{100000}{1000}$$
$$A_{v} = 1 + 100$$
$$A_{v} = 101$$

Therefore, the closed-loop voltage gain is 101.

37

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

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Answer & Solution

Answer: Option B

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38

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

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Answer & Solution

Answer: Option B

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39

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

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Answer & Solution

Answer: Option A

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40

A differential amplifier ___________

A) is a part of an Op-amp B) has one input and one output C) has two outputs D) A and B both

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Answer & Solution

Answer: Option D

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