# Analog Circuits (Test 3)

## Gate Exam : Ec Electronics And Communication Engineering

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Q.1
The approximate transfer characteristic for the circuit shown below with an ideal operational amplifier and diode will be A. B. C. D. Explaination / Solution:
No Explaination.

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Q.2
In the circuit shown below what is the output voltage  (vout)if a silicon transistor Q and an ideal op-amp are used? A. -15 V
B. -0.7 V
C. +0.7 V
D. +15 V
Explaination / Solution:

For the given ideal op-amp, negative terminal will be also ground (at zero voltage) and so, the collector terminal of the BJT will be at zero voltage.
i.e., VC = 0 volt
The current in 1 k resistor is given by
This current will flow completely through the BJT since, no current will flow into the ideal op-amp (I/P resistance of ideal op-amp is infinity). So, for BJT we have i.e.,the base collector junction is reverse biased (zero voltage) therefore, the collector current (IC ) can have a value only if base-emitter is forward biased.
Hence, Workspace
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Q.3
In the following transistor circuit, , and 𝛽 and all the capacitances are very large The mid-band voltage gain of the amplifier is approximately
A. -180
B. -120
C. -90
D. -60
Explaination / Solution:

The small signal model is shown in fig below Workspace
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Q.4
In the circuit shown below what is the output voltage out (Vout) in Volts if a silicon transistor Q and an ideal op-amp are used? A. -15
B. -0.7
C. +0.7
D. +15
Explaination / Solution:
No Explaination.

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Q.5
Given that the op-amp is ideal, the output voltage V0 is A. 4V
B. 6V
C. 7.5V
D. 12.12V
Explaination / Solution:
No Explaination.

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Q.6
The circuit below implements a filter between the input current ii and the output voltage v0. Assume that the opamp is ideal. The filter implemented is a A. low pass filter
B. band pass filter
C. band stop filter
D. high pass filter
Explaination / Solution:

From diagram we can write Transfer function Workspace
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Q.7
Assuming the OP-AMP to be ideal, the voltage gain of the amplifier shown below is A. B. C. D. Explaination / Solution: Workspace
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Q.8
In the circuit shown below the op-amps are ideal. Then Vout in Volts is A. 4
B. 6
C. 8
D. 10
Explaination / Solution:
No Explaination.

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Q.9
The transfer characteristic for the precision rectifier circuit shown below is (assume ideal OP-AMP and practical diodes) A. B. C. D. Explaination / Solution:  Workspace
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Q.10
Consider the common emitter amplifier shown below with the following circuit parameters:  The resistance seen by the source vs is
A. 258 Ω
B. 1258 Ω
C. 93 kΩ
D. 