POWER ELECTRONICS QUIZ

Maximum di / dt in a SCR is

inversely proportional to L in the circuit.

both A and C.

directly proportional to Vm of supply voltage.

inversely proportional to Vm of supply voltage.

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Snubber circuit is used with SCR

anti parallel.

either series or parallel.

in parallel.

in series.

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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.

1000 V/µs.

800 V/µs.

1200 V/µs.

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

0.67.

0.45.

0.32.

0.27.

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A diac has ___________ pn junctions

None of these

Three

Four

Two

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SCRs are used in series to meet

low current demand.

high current demand.

low voltage demand.

high voltage demand.

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An SCR is considered to be a semi controlled device because

it conducts only during one half cycle of an alternating current wave.

it can be turned ON but not OFF with a gate pulse.

it can be turned OFF but not ON with a gate pulse.

it can be turned ON only during one half cycle of an AC.

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Compared to transistor, ______________ have lower on state conduction losses and higher power handling capability

Semi conductor diodes.

Thyristor.

TRIACs.

MOSFETs.

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The latching current of GTO should be of order

1 A.

2 A.

500 mA.

100 mA.

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Under over voltage condition impedance offered by the voltage clamping device is

low.

infinity.

high.

moderate.

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