# 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

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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

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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

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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

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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

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Question 6

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

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

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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

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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

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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

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Question 10

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

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

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Question 11

High d(i)÷d(t) causes _______________

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

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Question 12

SCR is unipolar.

A. True
B. False

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Question 13

The most reliable method for thyristor triggering is thermal triggering.

A. True
B. False

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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

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Question 15

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

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

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