POWER ELECTRONICS QUIZ

4 thyristors rated 200 V in series. The operating voltage of the string is 0.600 V. Derating factor of the string is

0.7.

0.25.

0.75.

0.2.

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A Triac has three terminals viz ___________

None of these

Drain, source, gate

Two main terminal and a gate terminal

Cathode, anode, gate

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ON state voltage drop across SCR lie between the range

0 - 0.5 V.

1 - 1.5 V.

1.5 - 2 V.

0.5 - 1 V.

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Between the peak point and the valley point of UJT emitter characteristics we have ___________ region

None of these

Cut-off

Negative resistance

Saturation

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SITH is also known as

Filled controlled diode.

None of these.

Silicon controlled rectifier.

Filled controlled rectifier.

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A triac is equivalent to two SCRs ___________.

None of these

In parallel

In series

In inverse-parallel

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The device that exhibits negative resistance region is ___________.

UJT

Diac

Triac

Transistor

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A step up chopper has input voltage 110 V and output voltage 150 V. The value of duty cycle is

0.27.

0.45.

0.32.

0.67.

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The capacitance of reversed bised junction J2 in a thyristor is CJ2 = 20 pF and can be assumed to be independant of the off state voltage. The limiting value of the charging current to turn on the thyristor is 16 mA. What is the critical value of dv/dt?

600 V/µs.

800 V/µs.

1200 V/µs.

1000 V/µs.

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In forward blocking mode of a thyristor

junction J2 is in reverse bias and J1, J3 is in forward bias.

junction J3 is in forward bias and J1, J2 is in reverse bias.

Junction J1, J3 is in reverse bias and J2 is in forward bias.

Junction J1 and J2 is in forward bias and J3 is in reverse bias.

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