Voltage regulators - Electrical Engineering (MCQ) questions and answers

1)   The ac voltage controller can be used for

a. Lighting and heating control
b. On - line transformer tap changing
c. Soft starting
d. All of these
Answer  Explanation 

ANSWER: All of these

Explanation:
No explanation is available for this question!
2)   With increase in firing angle,

a. Both harmonic distortion and quality of input current increases
b. Harmonic distortion increases and quality of input current decreases
c. Harmonic distortion decreases and quality of input current increases
d. Both harmonic distortion and quality of input current decreases
Answer  Explanation 

ANSWER: Harmonic distortion increases and quality of input current decreases

Explanation:
No explanation is available for this question!
3)   The most suited gate pulses given to the AC regulator with R - L load can be in the form of

a. Continuous signal
b. Large isolating pulse transformer
c. A train of pulses
d. None of these
Answer  Explanation 

ANSWER: A train of pulses

Explanation:
No explanation is available for this question!
4)   The phase angle of gate signal in TRIAC can be shifted by using

a. A capacitor
b. A variable resistor
c. An inductor
d. Only (a) and (b)
Answer  Explanation 

ANSWER: Only (a) and (b)

Explanation:
No explanation is available for this question!
5)   A TRIAC can be turned on with

a. Positive voltage at the gate terminal
b. Negative voltage at the gate terminal
c. Either (a) or (b)
d. None of these
Answer  Explanation 

ANSWER: Either (a) or (b)

Explanation:
No explanation is available for this question!
6)   DIAC and TRIAC both are semiconductors devices and conduct in

a. DIAC conducts in forward direction and TRIAC conducts in reverse direction
b. Both conducts in forward direction
c. Both conducts in reverse direction
d. Both conducts in either direction
Answer  Explanation 

ANSWER: Both conducts in either direction

Explanation:
No explanation is available for this question!
7)   The maximum firing angle in the half wave controlled regulator is

a. 180 degree
b. 190 degree
c. 200 degree
d. 210 degree
Answer  Explanation 

ANSWER: 210 degree

Explanation:
No explanation is available for this question!
8)   In a phase controlled 3 phase ac voltage controller, the harmonic present is

a. 2nd
b. 3rd
c. 5th
d. 7th
Answer  Explanation 

ANSWER: 2nd

Explanation:
No explanation is available for this question!
9)   As the breakdown voltage reached, the DIAC exhibits

a. Negative resistance characteristics
b. Goes into avalanche condition
c. Voltage drop snaps back
d. All of these
Answer  Explanation 

ANSWER: All of these

Explanation:
No explanation is available for this question!
10)   DIAC are specifically designed to trigger

a. TRIAC
b. SCR
c. GTO
d. Only (a) and (b)
Answer  Explanation 

ANSWER: Only (a) and (b)

Explanation:
No explanation is available for this question!

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