Here are 100 theory-based multiple-choice questions (MCQs) with answers based on the
syllabus of Analog Electronic Circuits - II (PCCECE42), from the uploaded image. These are
divided according to the syllabus structure:
SECTION 1: Differential Amplifiers (Q1–Q20)
Q1. The main function of a differential amplifier is:
A. Amplify AC signals
B. Amplify the difference between two signals
C. Block DC components
D. Work as a switch
Ans: B
Q2. A MOS differential pair operates based on:
A. Collector current matching
B. Gate-source voltage difference
C. Threshold voltage mismatch
D. Feedback loops
Ans: B
Q3. Common mode rejection ratio (CMRR) is:
A. Gain of the differential signal
B. Ratio of differential gain to common-mode gain
C. Output resistance
D. Input offset
Ans: B
Q4. BJT differential amplifier offers better performance for:
A. High-frequency signals
B. High-power signals
C. Low-frequency small signals
D. Noisy environments
Ans: C
Q5. Common mode gain should ideally be:
A. High
B. Infinite
C. Zero
D. Unity
Ans: C
Q6. DC offset in differential amplifiers refers to:
A. Output resistance
B. Gain mismatch
C. Voltage difference when input is zero
D. Power dissipation
Ans: C
Q7. Differential amplifiers are primarily used in:
A. Logic gates
B. Oscillators
C. Operational amplifiers
D. Filters
Ans: C
Q8. Large signal analysis in BJT differential amplifiers considers:
A. Power rating
B. Non-linear characteristics
C. Noise figure
D. Capacitance
Ans: B
Q9. Active load in differential amplifier improves:
A. Frequency response
B. Input impedance
C. Gain
D. Output resistance
Ans: C
Q10. Tail current in differential amplifier is provided by:
A. Collector
B. Constant current source
C. Capacitor
D. Ground
Ans: B
Q11. Input resistance of a MOS differential amplifier is typically:
A. High
B. Low
C. Zero
D. Equal to output resistance
Ans: A
Q12. A differential pair requires:
A. Two independent supplies
B. Matched transistors
C. Positive feedback
D. Bipolar input
Ans: B
Q13. In differential amplifier, increasing tail current:
A. Decreases gain
B. Has no effect
C. Increases transconductance
D. Reduces bandwidth
Ans: C
Q14. Output of differential amplifier is ideally:
A. Half of input
B. Equal to one input
C. Proportional to voltage difference between inputs
D. Always positive
Ans: C
Q15. The gain of a differential amplifier with active load is:
A. Unity
B. Lower than passive load
C. Higher than passive load
D. Zero
Ans: C
Q16. Slew rate of differential amplifier depends on:
A. Input impedance
B. Output resistance
C. Bias current
D. Gain bandwidth product
Ans: C
Q17. Differential mode operation means:
A. Same voltage applied to both inputs
B. Inputs shorted
C. One input is grounded
D. Opposite voltages applied to inputs
Ans: D
Q18. Common mode operation means:
A. Same voltage applied to both inputs
B. Different voltages applied to inputs
C. Inputs shorted
D. Input grounded
Ans: A
Q19. Common mode rejection helps in:
A. Increasing output impedance
B. Amplifying noise
C. Reducing power
D. Eliminating noise in both inputs
Ans: D
Q20. Differential pair amplifiers are insensitive to:
A. Common-mode signals
B. Supply variations
C. Temperature
D. Load resistance
Ans: A
SECTION 2: Operational Amplifiers (Q21–Q40)
Q21. An ideal op-amp has:
A. Infinite gain
B. Zero input resistance
C. Zero output impedance
D. Both A and C
Ans: D
Q22. Voltage follower configuration is also known as:
A. Amplifier
B. Unity gain buffer
C. Inverter
D. Comparator
Ans: B
Q23. Open-loop gain of an ideal op-amp is:
A. 1
B. 10
C. 0
D. Infinite
Ans: D
Q24. An op-amp integrator output is:
A. Sum of input
B. Integral of input
C. Derivative of input
D. Constant
Ans: B
Q25. Instrumentation amplifier is designed for:
A. Power amplification
B. Audio processing
C. Accurate low-level signal amplification
D. Motor control
Ans: C
Q26. Inverting amplifier provides:
A. Unity gain
B. Positive gain
C. Negative gain
D. Zero gain
Ans: C
Q27. Closed loop gain in op-amp is set by:
A. Input voltage
B. Feedback resistor
C. Power supply
D. Load
Ans: B
Q28. Slew rate defines:
A. Max input voltage
B. Max rate of change of output voltage
C. Min gain
D. Output current
Ans: B
Q29. Differentiator circuit with op-amp gives:
A. Time integral
B. Constant output
C. Sine wave
D. Derivative of input
Ans: D
Q30. Weighted summer op-amp circuit:
A. Averages input
B. Multiplies inputs
C. Adds scaled inputs
D. Filters signals
Ans: C
Q31. Voltage follower has:
A. Infinite gain
B. Unity gain
C. Zero gain
D. Negative gain
Ans: B
Q32. The input impedance of an ideal op-amp is:
A. 0 Ω
B. Infinite
C. 1 MΩ
D. 50 Ω
Ans: B
Q33. An op-amp with negative feedback is:
A. Stable
B. Unstable
C. Noisy
D. Open loop
Ans: A
Q34. Bandwidth of op-amp decreases with:
A. Positive feedback
B. Gain
C. Load resistance
D. Bias current
Ans: B
Q35. Large signal behavior in op-amp is seen when:
A. Operating near supply rails
B. High frequency
C. High impedance
D. Low gain
Ans: A
Q36. ADC using op-amp is based on:
A. Integrator
B. Comparator
C. Summing amplifier
D. Differential amplifier
Ans: B
Q37. DAC using op-amp uses:
A. Weighted resistors
B. Capacitors
C. Transistors
D. Filters
Ans: A
Q38. Offset voltage in op-amp is due to:
A. Bias current
B. Mismatch in transistors
C. Supply ripple
D. Noise
Ans: B
Q39. Input bias current causes:
A. Output resistance to rise
B. Offset voltage
C. Positive gain
D. Current gain
Ans: B
Q40. Effect of bandwidth on op-amp:
A. Increases with gain
B. Decreases with gain
C. Remains constant
D. Independent of configuration
Ans: B
(Continued in next message...)
Continuing from Question 41 to 100, now covering:
● Section 3: Sinusoidal Oscillators
● Section 4: Waveform Shaping Circuits (Multivibrators)
● Section 5: Output Stages and Power Amplifiers
SECTION 3: Sinusoidal Oscillators (Q41–Q60)
Q41. The Barkhausen criterion states:
A. Loop gain < 1
B. Loop gain = 1 and phase shift = 0° or 360°
C. Negative feedback required
D. Gain must be zero
Ans: B
Q42. Sinusoidal oscillators generate:
A. Square wave
B. Triangular wave
C. Sine wave
D. Sawtooth wave
Ans: C
Q43. In RC phase shift oscillator, the feedback network contains:
A. Resistors and capacitors
B. Inductors
C. Transformers
D. Op-amps
Ans: A
Q44. Wien bridge oscillator uses:
A. RLC network
B. Twin-T network
C. Bridge circuit with RC components
D. Differentiator
Ans: C
Q45. Oscillator using LC tank circuit is:
A. Colpitts
B. Schmitt trigger
C. Integrator
D. Bistable
Ans: A
Q46. Crystal oscillators offer:
A. Variable frequency
B. High noise
C. Poor stability
D. Excellent frequency stability
Ans: D
Q47. Oscillator without feedback cannot:
A. Amplify
B. Generate sine wave
C. Start oscillation
D. Provide gain
Ans: C
Q48. Phase shift oscillator typically uses:
A. Transformer
B. Three RC stages
C. Diode
D. Square wave generator
Ans: B
Q49. In LC oscillators, frequency depends on:
A. Resistor value
B. Capacitor leakage
C. Inductance and capacitance
D. Op-amp gain
Ans: C
Q50. The main component for stability in a crystal oscillator is:
A. Feedback loop
B. Transformer
C. Quartz crystal
D. Varactor diode
Ans: C
Q51. Oscillator output is:
A. Zero
B. Non-periodic
C. Self-sustained periodic waveform
D. Noise only
Ans: C
Q52. Colpitts oscillator uses:
A. Two capacitors and one inductor
B. Two inductors and one capacitor
C. Three resistors
D. Op-amp only
Ans: A
Q53. Hartley oscillator uses:
A. RC feedback
B. Two inductors and one capacitor
C. Transistor bridge
D. Op-amp with RC
Ans: B
Q54. Phase shift of how many degrees is required for positive feedback in oscillators?
A. 0° or 360°
B. 90°
C. 180°
D. 270°
Ans: A
Q55. Wein bridge oscillator provides:
A. High distortion output
B. Highly stable waveform
C. Square waveform
D. Triangle waveform
Ans: B
Q56. Crystal oscillator operates on the principle of:
A. Electrical resonance
B. Magnetic field
C. Piezoelectric effect
D. Thermionic emission
Ans: C
Q57. The gain condition in Barkhausen criterion must be:
A. < 1
B. = 1
C. = 0
D. > 1
Ans: B
Q58. Wien bridge oscillator requires:
A. Active and passive components
B. Passive only
C. Feedback capacitor
D. External trigger
Ans: A
Q59. Oscillator startup needs:
A. DC offset
B. Noise or disturbance
C. Perfect balance
D. Capacitor pre-charging
Ans: B
Q60. Oscillators are different from amplifiers because they:
A. Do not require power
B. Need transformer
C. Have positive feedback
D. Always use op-amp
Ans: C
SECTION 4: Waveform Shaping Circuits – Multivibrators (Q61–Q80)
Q61. A bistable multivibrator has:
A. One stable state
B. No stable state
C. Two stable states
D. Three states
Ans: C
Q62. A monostable multivibrator has:
A. One stable and one quasi-stable state
B. No stable state
C. Two unstable states
D. One oscillating state
Ans: A
Q63. Astable multivibrator generates:
A. Single pulse
B. Stable output
C. Square wave continuously
D. No output
Ans: C
Q64. In 555 timer, the output frequency of astable mode depends on:
A. Input voltage
B. Feedback loop
C. External resistors and capacitor
D. Gain
Ans: C
Q65. In a 555 monostable multivibrator, the pulse width depends on:
A. Only capacitor
B. R and C values
C. Inductance
D. Load
Ans: B
Q66. A 555 timer in monostable mode is triggered by:
A. Output voltage
B. Control voltage
C. Input pulse
D. Supply change
Ans: C
Q67. Bistable multivibrators are used as:
A. Memory elements
B. Oscillators
C. Filters
D. Integrators
Ans: A
Q68. Transfer characteristic of bistable is:
A. Linear
B. Non-linear with hysteresis
C. Constant
D. Negative
Ans: B
Q69. In astable multivibrator using 555, the waveform is:
A. DC
B. Constant
C. Triangular
D. Square wave
Ans: D
Q70. Bistable multivibrator is also called:
A. Schmitt trigger
B. Flip-flop
C. Timer
D. Oscillator
Ans: B
Q71. Application of monostable multivibrator:
A. Memory
B. Pulse width modulation
C. Clock generation
D. Signal filtering
Ans: B
Q72. Multivibrators are examples of:
A. Amplifiers
B. Oscillators
C. Switching circuits
D. Attenuators
Ans: C
Q73. In monostable 555 circuit, once triggered:
A. Output stays HIGH for fixed time
B. Oscillates continuously
C. Output remains LOW
D. Input changes
Ans: A
Q74. 555 timer has how many comparators inside?
A. One
B. Two
C. Three
D. Four
Ans: B
Q75. Application of astable multivibrator is:
A. ADC
B. DAC
C. Clock generator
D. Voltage amplifier
Ans: C
Q76. In 555 IC, control voltage pin is:
A. 4
B. 5
C. 2
D. 3
Ans: B
Q77. 555 timer output is available at pin:
A. 2
B. 3
C. 5
D. 6
Ans: B
Q78. Triggering input of 555 timer is pin:
A. 2
B. 3
C. 4
D. 6
Ans: A
Q79. 555 IC operates typically at:
A. 1V
B. 9V
C. 18V
D. Both B and C
Ans: D
Q80. A free-running multivibrator is:
A. Monostable
B. Bistable
C. Astable
D. Inverter
Ans: C
SECTION 5: Output Stages and Power Amplifiers (Q81–Q100)
Q81. Class A amplifier conducts for:
A. 360° of input cycle
B. 180°
C. 90°
D. 270°
Ans: A
Q82. Class B amplifier conducts for:
A. 360°
B. 180°
C. 90°
D. 270°
Ans: B
Q83. Class AB is a combination of:
A. Class A and B
B. Class B and C
C. A and C
D. A and D
Ans: A
Q84. Class C amplifier conducts for:
A. Less than 180°
B. More than 270°
C. Full cycle
D. 90°
Ans: A
Q85. Class D amplifiers are:
A. Linear
B. Switching type
C. Analog
D. Digital only
Ans: B
Q86. Class A amplifiers have:
A. Highest efficiency
B. Lowest efficiency
C. No distortion
D. No power consumption
Ans: B
Q87. Power efficiency of Class B is around:
A. 10%
B. 25%
C. 78.5%
D. 100%
Ans: C
Q88. Crossover distortion occurs in:
A. Class A
B. Class B
C. Class D
D. Class C
Ans: B
Q89. Class AB amplifiers reduce:
A. Power
B. Gain
C. Crossover distortion
D. Input voltage
Ans: C
Q90. Power dissipation is lowest in:
A. Class A
B. Class AB
C. Class D
D. Class B
Ans: C
Q91. Output stage is needed in amplifier to:
A. Increase gain
B. Match impedance and drive load
C. Block noise
D. Act as filter
Ans: B
Q92. Power amplifier handles:
A. Voltage only
B. Small signals
C. High current and power
D. Logic levels
Ans: C
Q93. Transfer characteristic of power amplifier is:
A. Nonlinear
B. Linear
C. Constant
D. Logarithmic
Ans: B
Q94. IC regulators provide:
A. Variable voltage
B. Fixed voltage
C. Oscillation
D. Modulation
Ans: B
Q95. Output power depends on:
A. Input signal
B. Load resistance
C. Supply voltage
D. All of the above
Ans: D
Q96. Efficiency of amplifier is:
A. Input/Output power
B. Output/Input power
C. Voltage gain
D. Current gain
Ans: B
Q97. Class D amplifiers use:
A. Transistors in active region
B. PWM technique
C. Linear amplification
D. RC filters
Ans: B
Q98. Class C amplifiers are used for:
A. Audio
B. RF applications
C. Power supplies
D. Digital circuits
Ans: B
Q99. Heat sink is required in power amplifier to:
A. Amplify signal
B. Regulate output
C. Dissipate heat
D. Improve gain
Ans: C
Q100. Power conversion efficiency improves with:
A. Class A
B. Class B
C. Class AB
D. Class D
Ans: D
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