Power Electronics Objective Questions – Set 1

A single phase one pulse controlled circuit has a resistance R and counter emf E load 400 sin(314 t) as the source voltage. For a load counter emf of 200 V, the range of firing angle control is

Leakage current flows through the thyristor in

An SCR has half cycle surge current rating of 3000 A for 50 Hz supply. One cycle surge current will be

The typical value of SCR for modern alternator is

Light triggering mainly used in

In a P₁N₁P₂N2 thyristor which layer is less doped ?

The latching current of SCR is 20 mA. Its holding current will be

SCR will be turned off when anode current is

Gate circuit or triggering circuit of a thyristor is

What is used to protect the SCR from over current ?

Switching frequency of SITH is

Practical way of obtaining static voltage equalization in series connected SCRs is by the use of

CB used for over current protection of thyristor operates when the fault current is

A single phase full bridge inverter can operate in load commutation mode in case load consists of

Which triggering is the most reliable?

The latching current of GTO should be of order

In reverse blocking mode of a thyristor

A single phase full bridge inverter can operated in load commutation mode in case load consist of

An SCR is considered to be a semi controlled device because

After proper turn on of thyristor

When a large surge current of very short duration flows through a thyristor then which one of the following device will operate to protect the thyristor ?

Under normal operating condition voltage clamping device offers impedance of

The function of snubber circuit connected across the SCR is to

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

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

In forward blocking mode of a thyristor

Thyristor can be protected from over voltages by using

Example of a voltage clamping device

Which statement is true for latching current ?

If holding current of a thyristor is 2 mA then latching current should be