POWER ELECTRONICS QUIZ

What happen due to high di / dt?

Insulation failure.

None of these.

Local hot spot.

Breakdown of junction.

TRUE ANSWER : ?
YOUR ANSWER : ?

Power transistor are type of

All of above.

IGBTs.

BJTs.

MOSFETs.

TRUE ANSWER : ?
YOUR ANSWER : ?

Which of following is not a power transistor?

TRIAC.

IGBTs.

SITS.

COOLMOS.

TRUE ANSWER : ?
YOUR ANSWER : ?

A thyristor string is made of a no. of SCR connected in series and parallel. The string have volume and current of 11 KV and 4 KA. The voltage and current rating of available SCRs are 1800 V and 1000 A. For a string efficiency of 90 % let the number of SCRs in series and parallel are a and b respectively. Then the value of a and b will be

4, 6.

7, 5.

5, 7.

6, 4.

TRUE ANSWER : ?
YOUR ANSWER : ?

Which of the following is used in SCR to protect from high dV / dt?

Circuit breaker.

Equalizing circuit.

Snubber circuit.

Fuse.

TRUE ANSWER : ?
YOUR ANSWER : ?

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

Semi conductor diodes.

MOSFETs.

Thyristor.

TRIACs.

TRUE ANSWER : ?
YOUR ANSWER : ?

A triac can pass a portion of ___________ half-cycle through the load.

Only negative

None of these

Both positive and negative

Only positive

TRUE ANSWER : ?
YOUR ANSWER : ?

Delay time is defined by the interval when

anode voltage drops from 100 % to 90 % of its actual value.

anode current reaches 10 % from forward leakage current.

all of these.

gate current increases from 90 % to 100 % of its final value.

TRUE ANSWER : ?
YOUR ANSWER : ?

During which time maximum conduction spreading take place in the thyristor during turn ON?

Spread time.

Delay time.

Rise time.

Same for every case.

TRUE ANSWER : ?
YOUR ANSWER : ?

Thyristor can be protected from over voltages by using

snubber circuit.

voltage clamping device.

heat sink.

fuse.

TRUE ANSWER : ?
YOUR ANSWER : ?