# di/dt & dv/dt Protection MCQ Questions & Answers

di/dt & dv/dt Protection MCQs : This section focuses on the "di/dt & dv/dt Protection". These Multiple Choice Questions (MCQs) should be practiced to improve the di/dt & dv/dt Protection skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.

Question 1

____________ is the switching frequency of SITH.

A. 55 KHz
B. 100 KHz
C. 91 KHz
D. 105 KHz

Question 2

25 V rated n SCRs are connected in series. The operation voltage of the string is 300 V and the string efficiency is 40 %. Calculate the value of n.

A. 27
B. 30
C. 34
D. 36

Question 3

A step-down chopper has input voltage 12 V and output voltage 2 V. Calculate the value of the duty cycle.

A. 0.26
B. 0.16
C. 0.33
D. 0.41

Question 4

Calculate the De-rating factor if the string efficiency is 90 %.

A. 0.4
B. 0.1
C. 0.7
D. 0.8

Question 5

Calculate the output voltage of the Boost converter if the supply voltage is 1 V and duty cycle value is .9.

A. 10 V
B. 20 V
C. 40 V
D. 60 V

Question 6

Calculate the string efficiency if the de-rating factor is .22.

A. 78 %
B. 42 %
C. 20 %
D. 90 %

Question 7

Calculate the value of Crest factor if Vpeak=1.5 V and Vr.m.s=2.5 V.

A. 0.4
B. 0.6
C. 0.5
D. 0.7

Question 8

Calculate the value of output r.m.s voltage for Single phase Full-bridge inverter if the DC supply is 25 V.

A. 26 V
B. 25 V
C. 27 V
D. 28 V

Question 9

Calculate the value of output r.m.s voltage for Single phase Half-bridge inverter if the DC supply is 80 V.

A. 40 V
B. 20 V
C. 10 V
D. 60 V

Question 10

Device with highest d(i)÷d(t) and d(v)÷d(t) capability is _____________

A. GTO
B. BJT
C. SCR
D. SITH

Question 11

High d(i)÷d(t) causes _______________

A. Local hotspots
B. Breakdown
C. High cost
D. Low cost

Question 12

SCR is unipolar.

A. True
B. False

Question 13

The most reliable method for thyristor triggering is thermal triggering.

A. True
B. False

Question 14

What is the formula for thermal voltage?

A. K×e÷T
B. K×T÷e
C. K2×e÷T
D. K×e2÷T