Vidyasagar Sir’s open book test | You will be compelled to study & understand topics, then only you can solve this test.
XII Objective Test
Name of Student ___________________________
Operational Amplifiers
Batch Time___________, Marks obtained ______
Time: 80 minutes
Marks: 96
All questions are compulsory. Each question carries TWO mark.
If more than one alternative is tickmarked, its marks will NOT be counted.
1.
2.
3.
4.
5.
A differential amplifier is –
A. symmetrical circuit
B. asymmetrical circuit
C. feedback circuit
D. attenuator circuit
Following is the basic property of virtual ground
terminal of opamp –
A. it has high impedance
B. it has negative potential
C. it produces ac voltage
D. it cannot absorb current
The feedback used in non-inverting amplifier
circuit using opamp is called as –
A. positive feedback
B. ac feedback
C. resistive feedback
D. negative feedback
a
s
When gain of an amplifier tends to vary with
frequency, such amplifier is categorized as –
v
C. single ended
7.
8.
When single power supply is used for a
differential amplifier, following problem is
observed A. frequency response changes
B. distortion is produced
C. temperature of the device increases
D. operating point changes
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10. The potential difference between inverting and
non-inverting terminal of opamp is equal to –
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A. infinite
B. positive
C. zero
D. negative
11. For a practical opamp, one of the following
statements is true –
A. bias current is not zero
B. propagation delay is zero
C. offset voltage is zero
D. closed loop gain is infinite
a
g
For a bipolar transistor, its Vce and Ic are –
A. inversely proportional
B. directly proportional
C. equal to each other
D. independent of each other
A. dc amplifier
6.
9.
12. When multistage amplification is done –
A. output current increases
B. drift is produced
C. dc voltage level increases
D. distortion decreases
B. double ended
D. RC coupled
For a differential amplifier, its __________ is
independent of frequency.
A. input impedance
B. loading effect
C. frequency response
D. temperature drift
CMRR is the ratio of –
13. In an inverting adder, if all the resistors used in
the circuit have unequal values, then its gain will
be –
A. other than unity
B. zero
C. equal to unity
D. unity
14. For a buffer circuit using opamp, following
condition is true –
A. ACM to ADM
B. Vout to Vin
A. Ri = 0
B. closed loop gain > 1
C. Pout to Pin
D. ADM to ACM
C. Vo = Vi
D. Rf = 1
A low pass filter circuit can be constructed using -
15. Bandwidth of an amplifier is equal to -
A. differentiator
B. inverting amplifier
A. CMRR
B. fH – fL
C. integrator
D. summing amplifier
C. fL – fH
D. zero
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Vidyasagar Sir’s open book test | You will be compelled to study & understand topics, then only you can solve this test.
16. If Vref > Vi, Vo = +Vsat: this statement is true for
which of the following comparator
A. inverting non-zero reference comparator
B. inverting zero reference comparator
C. non-inverting zero reference comparator
D. non-inverting non-zero reference comparator
17. In inverting amplifier virtual ground exists
because –
A. closed loop gain is finite
B. feedback is positive
C. open loop gain is infinite
D. Vo = –Vsat
18. In the block diagram of opamp, the output stage
is used to satisfy A. Maximum power transfer theorem
B. Superposition theorem
C. Norton’s theorem
D. Thevenin’s theorem
19. For a non-inverting amplifier, if Rf = R1 = 10Ω, and
Vo = –1.5V, then –
A. Vi = 10V
B. Vi = –0.75V
C. Vi = –3.0V
D. Vi = 0.75V
A. low voltage
A. ac signals
B. human voice signal
C. irregular wave
D. dc signal
a
s
21. The group of second differential amplifier, emitter
follower and level shifter in opamp is called as –
A. output stage
B. intermediate stage
C. cascading circuits
D. gain control circuit
22. In practical opamp, the output offset voltage is
measured when –
A. supply voltage is minimum
B. input terminals are grounded
C. input signals are applied
D. temperature is equal to 25C
23. In the circuit of Schmitt trigger using opamp,
when output voltage Vo = –Vsat i.e. negative
saturation of output, the voltage on the noninverting terminal will be –
A. –(Vsat)
B. –Vsat
C. +Vsat
D. UTP voltage
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B. high frequency
C. high gain
D. peak amplitude
25. An amplifier can be used to amplify very small
signals if its –
A. input impedance is very high
B. gain is zero
C. frequency response is high
D. output impedance is zero
26. The emitter follower stage in operational
amplifier provides –
A. high output current
B. good frequency response
C. high CMRR
D. low input impedance
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27. To plot the frequency response curve of opamp,
its voltage gain is generally expressed in –
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A. decibel
B. Watt
C. Hertz
D. Ampere
28. The phase difference between input and output
signal of a buffer circuit using opamp, is –
a
g
20. RC coupled amplifier cannot be used to amplify –
v
24. When slew rate of operational amplifier is low, it
produces distortion particularly at –
A. 90
B. unity
C. 0
D. 280
29. The unit of slew rate is –
A. sec/volt
B. volt/
C. /sec
D. volt/sec
30. The open loop gain of practical opamp changes
due to change in –
A. feedback fraction
B. frequency
C. input currents
D. power supply voltage
31. The output voltage of differential amplifier is
double than its input voltage when –
A. V1 = V2
B. V1 > V2
C. V1 = –V2
D. (V1 – V2) < 0
32. The difference between UTP & LTP is called as –
A. saturation voltage
B. propagation delay
C. hysteresis
D. drift
33. The CMRR of ideal opamp is –
A. infinite
B. unity
C. always finite
D. zero
Vidyasagar Sir’s open book test | You will be compelled to study & understand topics, then only you can solve this test.
34. When two unequal signals are applied at the two
input terminals of a differential amplifier, its gain
will be –
A. infinite
B. zero
C. less than infinity
D. unstable
35. The _________ parameter of practical operational
amplifier is measured, keeping its input voltages
equal to zero –
A. output offset voltage
B. input bias current
C. input offset current
D. open loop gain
36. According to Coulomb’s law, the current flowing
through a capacitor is proportional to –
A. capacity of capacitor
B. rate of change of applied voltage
C. rate of change of temperature
D. frequency
37. To convert sine wave into square wave following
circuit is suitable –
A. differentiator
B. comparator
C. integrator
D. Schmitt trigger
A. infinite
B. unity
C. zero
D. finite
42. Connecting the fraction of output back to the
input of opamp is called as –
A. drift
B. gain
C. feedback
D. bootstrapping
43. Due to two types of amplifier circuits, there can
be two types of feedbacks, they are –
A. positive & negative feedback
B. negative feedback & gain
C. gain & positive feedback
D. stable feedback & unstable feedback
a
s
39. The closed loop gain of ideal opamp is –
A. proportional to input bias current
B. equal to the ratio of Rf to R1
C. stable
D. independent of temperature
v
40. In inverting summing amplifier circuit, if there are
three input voltages V1, V2 and V3 equal to 1V,
2V and 3V respectively. If all the resistors used in
the circuit have equal values, then the output
voltage of the circuit will be –
A. Vo = 6V
B. Vo = –1.8V
C. Vo = –6V
D. Vo = 12V
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A. square, sine
B. sawtooth, triangular
C. sine, square
D. triangular, sine
45. Integrator is the circuit used to convert ______
wave into _________ wave.
A. square, sine
B. sawtooth, triangular
C. sine, square
D. square, triangular
46. When the feedback resistance in a non-inverting
amplifier circuit is equal to zero, then the circuit
acts as –
A. comparator
B. differentiator
C. buffer
D. inverting amplifier
47. _______ of an operational amplifier is defined as
the gain with feedback.
A. closed loop gain
B. open loop gain
C. offset voltage
D. drift
48. For an ideal operational amplifier, the output
offset voltage should be always ________.
A. zero
B. equal to unity
C. infinity
D. less than unity
The answer keys of this paper are given on our website.
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g
r
44. The comparator circuit using opamp can be used
to convert _______wave into ________ wave.
a
g
38. The open loop gain of a comparator is the equal
to the ratio of –
A. Vsat to Vi
B. Vo to Vi
C. Vref to closed loop gain
D. Vsat to ACL
41. Input resistance of ideal opamp is –
Vidyasagar Sir’s open book test | You will be compelled to study & understand topics, then only you can solve this test.
XII BIFOCAL ELECTRONICS
ANSWER KEYS
OPERATIONAL AMPLIFIER
1.
A
2.
D
3.
A
4.
A
5.
A
6.
C
7.
D
8.
C
9.
B
10.
C
11.
A
12.
C
13.
A
14.
C
15.
B
16.
A
17.
C
18.
A
19.
D
20.
D
21.
B
22.
B
23.
A
24.
B
25.
26.
A
27.
A
28.
C
29.
D
30.
31.
C
32.
C
33.
A
34.
C
35.
36.
B
37.
B
38.
D
39.
B
40.
41.
A
42.
C
43.
A
44.
C
45.
46.
C
47.
A
48.
A
a
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o
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r
Best of Luck!
a
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v
Vidyasagar Academy’s Question Papers: www.vsagar.org
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A
B
A
C
D