# Power Electronics MCQs Part 2

Power Electronics MCQs Part 2

## Of following, the device that does not belong to the transistor family is

Of following, the device that does not belong to the transistor family is

1. BJT
2. GTO
3. IGBT
4. MOSFET

Explanation: GTO or gate turn off switch (GTO) belongs to Thyristors. Thyristors are a broad classification of bipolar-conducting semiconductor devices having four (or more) alternating N-P-N-P layers. Thyristors include: silicon controlled rectifier (SCR), TRIAC, gate turn off switch (GTO), silicon controlled switch (SCS), AC diode (DIAC), unijunction transistor (UJT), programmable unijunction transistor (PUT). Continue reading full article on Thyristors.

## Dynamic equalizing circuit is used for

Dynamic equalizing circuit is used for

1. Equal division of voltage across each thyristor
2. Equal division of current through each thyristor in parallel
3. Equal division of voltage across each thyristor in parallel
4. Equal division of current through each thyristor in series

Correct answer: 1. Equal division of voltage across each thyristor

Explanation: Dynamic equalizing circuit is a snubber circuit that is used to equalize the voltage division under transient condition.

Recommended reading: Shockley Diode Construction and Working

## IGBT combines the advantages of

1. BJTs and SITs
2. SITs and MOSFETs
3. BJTs and MOSFETs
4. None of these

Correct answer: 3. BJTs and MOSFETs

Explanation: IGBT combines the advantage of both BJTs and MOSFETs: Click here to Read ElectricalEngineering.XYZ’s article on MOSFET. IGBT possesses high input impedance like a MOSFET and has low on state power loss as in a BJT.

## Which of following devices has highest di/dt and dv/dt capability

Which of following devices has highest di/dt and dv/dt capability:

1. GTO
2. SIT
3. SITH
4. SCR

Explanation:

The static induction is thyristor with a buried gate structure in which the gate electrode are placed in n-base region. They have high di/dt and dv/dt rating. You might like reading Semiconductor Manufacturing Techniques

## The SCR is considered as semi controlled device since

The SCR is considered as semi controlled device since

1. It can be turned on but not off with a gate pulse
2. It can be turned off but not on with a gate pulse
3. It conducts only during half cycle of an alternating current wave
4. It can be turned on only during one half cycle of an ac

Correct answer: 1. It can be turned on but not off with a gate pulse

Explanation:

During positive half cycle SCR is in forward blocking mode. By applying gate pulse the SCR can be turned ON.

However, SCR cannot be turned OFF by applying gate pulse. Rather, it automatically turns off when anode current is below the Holding current.

That is the reason SCR is called semi-controlled rectifier.

See More Electrical Engineering MCQs: