Power Electronics MCQ Questions & Answers

41

An UJT, the p-type emitter is . . . . . . . . doped

A) Lightly B) Heavily C) Moderately D) None of the above

Discuss

Answer & Solution

Answer: Option B

No explanation is given for this question. Let's Discuss on Board

42

A single-phase full-wave AC phase controller feeds power to a resistive load of 100 Ω from a 220 V, 50 Hz supply. What will be the rms output voltage at delay angles $${\alpha _1} = {\alpha _2} = \alpha = \frac{\pi }{2}$$ of both transistors?

A) $$\frac{{220}}{{\sqrt 2 }}{\text{V}}$$ B) $$\sqrt {2 \times 220} {\text{ V}}$$ C) $$\sqrt 2 \times 110{\text{ V}}$$ D) $$\sqrt 2 \times 220{\text{ V}}$$

Discuss

Answer & Solution

Answer: Option A

No explanation is given for this question. Let's Discuss on Board

43

Consider the following statements:
A four-layer PNPN device having two gate leads can turned on by applying a
1. positive current pulse to the cathode gate
2. positive current pulse to the anode gate
3. negative current pulse to the anode gate
4. negative current pulse to the cathode gate
Which of these statements is/are correct?

A) 1 alone B) 1 and 3 C) 2 alone D) 2 and 4

Discuss

Answer & Solution

Answer: Option D

No explanation is given for this question. Let's Discuss on Board

44

A Silicon Controlled Resistor (SCR) is made up of silicon and not germanium because

A) silicon is inexpensive B) silicon is mechanically strong C) silicon has small leakage current D) silicon is tetravalent

Discuss

Answer & Solution

Answer: Option C

No explanation is given for this question. Let's Discuss on Board

45

An a.c. regulator can be designed with

A) two diodes B) two tunnel diodes C) two zener diodes D) none of these

Discuss

Answer & Solution

Answer: Option C

No explanation is given for this question. Let's Discuss on Board

46

The gate current required to turn on an SCR is

A) Few amperes B) Few milliamperes C) Almost equal to anode current D) About 50% of anode current

Discuss

Answer & Solution

Answer: Option B

No explanation is given for this question. Let's Discuss on Board

47

A freewheeling diode in a phase controlled rectifier

A) improves the line power factor B) enables inverse operation C) is responsible for additional reactive power D) is responsible for additional harmonics

Discuss

Answer & Solution

Answer: Option A

No explanation is given for this question. Let's Discuss on Board

48

Consider the following statements: An SCR, from its OFF state, can be made ON by-
1. increasing its anode voltage
2. increasing its gate current
3. decreasing its gate voltage
4. decreasing its anode current
Which one of the following statements is correct?

A) Either 1 or 2 B) Either 1 or 3 C) Either 2 or 4 D) Either 3 or 4

Discuss

Answer & Solution

Answer: Option A

No explanation is given for this question. Let's Discuss on Board

49

Power diode are used with

A) heat sinks B) reverse bias C) forward bias D) at room temperature

Discuss

Answer & Solution

Answer: Option A

No explanation is given for this question. Let's Discuss on Board

50

Match List-I with List-II and select the correct answer using the options given below:

List-I (SCR Rating)	List-II (Protective element)
a. di/dt limit	1. Snubber circuit
b. dv/dt limit	2. Heat sink
c. i²t limit	3. Series reactor
d. Junction temperature limit	4. Fuse

A) a-3, b-1, c-2, d-4 B) a-3, b-1, c-4, d-2 C) a-1, b-3, c-4, d-2 D) a-1, b-3, c-2, d-4

Discuss

Answer & Solution

Answer: Option B

No explanation is given for this question. Let's Discuss on Board

Power Electronics MCQ Questions & Answers | ECE