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Free download in PDF Amplifier Multiple Choice Questions and Answers for competitive exams. These short objective type questions with answers are very important for Board exams as well as competitive exams of Engineering. These short solved questions or quizzes are provided by Gkseries.
(1)
A differential amplifier ……………..
[A]
is a part of an Op-amp
[B]
has one input and one output
[C]
has two outputs
[D]
answers (1) and (2)
Answer: answers (1) and (2)
(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)
If ADM = 3500 and ACM = 0.35, the CMRR is ……….
[A]
1225
[B]
10,000
[C]
80 dB
[D]
answers (1) and (3)
Answer: answers (1) and (3)
(4)
With zero volts on both inputs, an OP-amp ideally should have an output ………..
[A]
equal to the positive supply voltage
[B]
equal to the negative supply voltage
[C]
equal to zero
[D]
None of the above
(5)
A certain OP-amp has bias currents of 50 μA. The input offset current is ……..
[A]
700 nA
[B]
99.3 μA
[C]
49.7 μA
[D]
none of these
(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]
None Of The Above
Answer: fed back to the inverting input
(8)
The use of negative feedback ………
[A]
reduces the voltage gain of an Op-amp
[B]
makes the Op-amp oscillate
[C]
makes linear operation possible
[D]
answers (1) and (2)
Answer: answers (1) and (2)
(9)
The gain of an amplifier without feedback is 100 db. If a negative feedback of 3 db is applied, the gain of the amplifier will become …………..
[A]
5 db
[B]
300 db
[C]
97 db
[D]
None of the Above
(10)
The value of negative feedback fraction is always …………….
[A]
Less than 1
[B]
More than 1
[C]
Equal to 1
[D]
None Of The Above
(11)
When negative voltage feedback is applied to an amplifier, its voltage gain ……………….
[A]
Is increased
[B]
Is reduced
[C]
Remains the same
[D]
None of the above
(12)
Current cannot flow to ground through …….
[A]
a mechanical ground
[B]
an a.c. ground
[C]
a virtual ground
[D]
None of the above
(13)
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
Answer: differential amplifier
(14)
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
(15)
A common-mode signal is applied to ……….
[A]
the noninverting input
[B]
the inverting input
[C]
both iputs
[D]
top of the tail resistor
(16)
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]
None of the above
Answer: sum of two emitter currents
(17)
The tail current 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
Answer: two times either collector current
(18)
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 the above
Answer: difference between two base currents
(19)
Negative feedback ………..
[A]
increases the input and output impedances
[B]
increases the input impedance and bandwidth
[C]
decreases the output impedance and bandwidth
[D]
None of the above
Answer: increases the input impedance and bandwidth
(20)
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
Answer: an identical signal appears on both the inputs
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