Test: Power Electronics - 6 - Electrical Engineering (EE) MCQ

A dc chopper is feeding an RLE load. The current can become discontinuous if

Which of these commutation methods uses two leads?

A single phase half wave rectifier is feeding a resistive load. As firing angle is increased

A cycloconverter for single phase operation has

A chopper is a high efficiency circuit.

The difference between resonant commutation and self commutation is

If 0.5 T is the time period of oscillations and T_off is the time between turn off of one thyristor and turn on of second thyristor, the frequency of output f of a series inverter is

In a series inverter

A NAND gate has 3 inputs and one output. The number of thyristors required for this gate are

Which of these devices is used in relaxation oscillator?

In auxiliary commutated chopper fed by voltage V and having L and C commutating elements, the peak value of capacitor current is

In a single phase semiconverter feeding a highly inductive load, the load current is

Two thyristors of the same rating and specifications

A 3 phase induction motor is controlled by voltage and frequency control such that the ratio V/f is constant. At 50 Hz, the starting torque is 100 N-m. At 25 Hz, the starting torque

In a three phase to single phase full wave bridge cycloconverter, the number of thyristors is

A single phase half wave converter is feeding-a resistor load. The input voltage is v = V_m sin ωt. If firing angle is zero, the output dc voltage V_dc and output rms voltage V_rms respectively

In a cycloconverter it is possible to vary

A single phase full bridge inverter for R-L loads needs

In the basic series inverter circuit, the source current has

Thyristors connected in series need static and dynamic stabilizing circuits.

In a controlled rectifier a freewheeling diode is necessary if the load is

For an illumination control circuit it is advisable to use a matched TRIAC-DIAC pair.