# Phase Locked Loop MCQ [Free PDF] – Objective Question Answer for Phase Locked Loop Quiz

71. Find the lock-in range of the monolithic Phase-Locked Loop from the given diagram.

A. -fo-△fL to fo-△fL
B. -fo-△fL to -fo-△fC
C. fo-△fL to fo-△fC
D. -fo-△fC to fo-△fC

Lock-in range of monolithic PLL is from

-fo-△fL to fo-△fL.

72. At what range the PLL can maintain the lock in the circuit?

A. Lock in range
B. Input range
C. Feedback loop range
D. None of the mentioned

The change in frequency of the incoming signal can be tracked when the PLL is locked. So, the range of frequencies over which PLL maintains the lock with the incoming signal is called the lock-in range.

73. At which state the phase-locked loop tracks any change in input frequency?

A. Free running state
B. Capture state
C. Phase-locked state
D. All of the mentioned

In the phase-locked, the output frequency is the same as the input signal frequency. So the circuit tracks any change in the input frequency through its repetitive action.

74. Output current in general-purpose op-amp can be increased using.

A. Power comparator
B. Power amplifier
C. Power resistor
D. Power booster

A simple method of increasing the output current of a general-purpose op-amp is to connect a power booster in series with the op-amp.

75. Which type of power transistor is chosen for a discrete power booster?

A. Collector follower stage
B. Emitter follower stage
C. Base follower stage
D. None of the mentioned

A discrete power booster is formed by an emitter follower stage using a power transistor. Because of unity gain, the emitter follower helps to retain the voltage gain characteristics of the general-purpose op-amp.

76. What is the power dissipation of the power transistor?

A. ≅ 0.5W
B. ≤ 0.5W
C. > 0.5W
D. ≠ 0.5W

Transistors with power dissipation larger than 1/2 (0.5)W are called power transistors.

77. Burr-Brown 3553 power amplifier is suited for

A. Line driving applications
B. Power supply requirement
D. High-frequency application

Burr-Brown 3553 power amplifier is suited for line driving applications in which fast pulses or wideband signals are involved.

78. Find the IC that can be used for short circuit proof protection?

A. All of the mentioned
B. IC LM384
C. ICL8063
D. ICLM380

The Intersil ICL8063 monolithic power transistor driver and amplifier has built-in safe area protection and short-circuits proof protection.

79. Which of the following is ideal for consumer applications?

A. NE5018
B. LM380
C. MC1408
D. SE5018

LM380 is a power audio amplifier designed to deliver a minimum of 2.5w to an 8Ω load and hence is ideal for consumer applications.

80. Bridge power audio amplifier can deliver power up to

A. Twice as much as the output of a single LM380 amplifier
B. Thrice as much as the output of a single LM380 amplifier
C. Four times as much as the output of a single LM380 amplifier
D. Half of the output of a single LM380 amplifier

Two LM380s are used in the bridge configuration. Therefore, it produces a maximum output voltage swing that is equal to twice that of a single LM380 amplifier.

81.  What precautionary measures should be taken if the circuit is used in an RF-sensitive environment?

A. Connect a parallel combination of RC at the output
B. Connect a series combination of Resistors at the output
C. Connect parallel capacitor at the output
D. Connect a series combination of RC at the output

When the LM380 audio power amplifier is used in an RF-sensitive environment, an RC combination should be added at the output terminal (Pin 8) to eliminate 5 to 10-MHz oscillation.

82. Which amplifier provides twice the output swing as that of the LM380 amplifier?

A. Hybrid power amplifier
B. Bridge power audio amplifier
C. Monolithic power audio amplifier
D. Dual power amplifier

In the bridge power audio amplifier, two LM380s are used in a bridge configuration. Therefore, the maximum output voltage swing will be twice that of a single LM380 amplifier.

83. A LM380 power amplifier is used in an intercom system with amplifier gain = 50 and the transformer turns ratio is given as 35. Find the overall gain of the circuit.

A. 1880
B. 1750
C. 1370
D. 1580

Given, N1/N2=35

Gain of amplifier = 50.

Therefore, the overall gain of the circuit = 50×35 =1750.

84. Determine the work done by the intercom system depending on the position of the switch

A. Remote speaker acts  as a microphone
B. Master speaker acts  as a microphone
C. Remote and master speaker act as a microphone
D. None of the mentioned