20 Questions | Total Attempts: 209  Settings  • 1.
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

• 2.
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

• 3.
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

• 4.
If ACM = 0.35 and ADM = 3500, the CMRR is
• A.

80dB

• B.

40dB

• C.

20dB

• D.

100dB

• 5.
The slew rate of an op-amp whose output increases 8V in 12μs is
• A.

90 V/μs

• B.

0.67 V/μs

• C.

1.5 V/μs

• D.

None of these

• 6.
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 non-inverting input

• 7.
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

• 8.
The Op-amp can amplify
• A.

A.c. signals only

• B.

D.c. signals only

• C.

Both a.c. and d.c. signals

• D.

Neither d.c. nor a.c. signals

• 9.
The current flowing through emitter resistance of a differential amplifier is …….
• A.

Half of either collector current

• B.

Equal to either collector current

• C.

Two times either collector current

• D.

Equal to the difference in base currents

• 10.
An astable multivibrator is also known as a
• A.

One-shot multivibrator

• B.

Free-running multivibrator…

• C.

Bistable multivibrator

• D.

Monostable multivibrator

• 11.
What starts a free-running multivibrator?
• A.

An input signal

• B.

A trigger

• C.

An external circuit

• D.

Nothing

• 12.
What is the cutoff frequency of the low pass filter in the following circuit
• A.

4.8 kHz

• B.

3.8 kHz

• C.

2.8 kHz

• D.

1.8 kHz

• 13.
What is the frequency of this 555 astable multivibrator?
• A.

241 Hz

• B.

178 Hz

• C.

241 kHz

• D.

178 kHz

• 14.
If the input to a comparator is a sine wave, the output is a
• A.

Ramp voltage

• B.

Sine wave

• C.

Rectangular wave

• D.

Sawtooth wave

• 15.
The Schmitt trigger is a two-state device used for
• A.

Pulse shaping

• B.

Peak detection

• C.

Input noise rejection

• D.

Filtering

• 16.
A circuit that uses an amplifier with passive filter elements is called a/an:
• A.

Relaxation oscillator

• B.

Signal generator

• C.

Active filter

• D.

Differentiator

• 17.
A low pass filter is one that passes all the frequencies from
• A.

A fixed frequency to ∞

• B.

0 to fixed higher frequency

• C.

A fixed lower frequency to fixed higher frequency

• D.

All frequencies

• 18.
A high pass filter is one that passes all the frequencies from
• A.

A fixed frequency to ∞

• B.

0 to a fixed higher frequency

• C.

A fixed lower frequency to fixed higher frequency

• D.

All frequencies

• 19.
A passive filter makes use of
• A.

RC networks

• B.

RLC networks

• C.

LC networks

• D.

All of the above

• 20.
Calculate the cutoff frequency of a first-order low-pass filter for R1 = 2.5 kΩ and C1 = 0.05 µF
• A.

1.273 kHz

• B.

12.73kHz

• C.

127.3kHz

• D.

1237 kHz.

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