Single-Phase Rectifiers Quiz

In a single-phase half-wave controlled rectifier, the thyristor is turned on during:

• Positive half cycle

• Negative half cycle

• Both half cycles

• When voltage is zero

The main function of a single-phase thyristor-controlled rectifier is to:

• Invert DC to AC

• Convert DC to DC

• Convert AC to controlled DC

• Step-up AC voltage

The delay angle (α) in a thyristor rectifier is defined as the angle at which:

• Thyristor is off

• Thyristor is triggered

• Load current is zero

• Thyristor is in reverse bias

For a single-phase half-wave controlled rectifier with RL load, if the firing angle (α) is increased, the output DC voltage:

• Increases

• Decreases

• Remains constant

• Is unaffected by α

The average output voltage in a single-phase fully controlled rectifier with a resistive load is given by:

• Vmsin(α)

• Vmcos(α)

• (Vm/π)(1+cos(α))

• (Vm/π)(1−cos(α))

In a single-phase half-wave controlled rectifier, the average DC output voltage can be controlled by:

• Changing load resistance

• Changing firing angle of the thyristor

• Changing the input frequency

• Adding capacitors

In a single-phase full-wave controlled rectifier with RL load, the output waveform typically contains:

• Only DC

• DC and fundamental frequency AC

• High-frequency AC only

• Pure AC

In a single-phase fully controlled bridge rectifier with resistive load, if the firing angle is zero, the output voltage waveform resembles:

• Full sine wave

• Half sine wave

• Positive DC with ripples

• Negative DC

A single-phase full-wave rectifier provides an average output voltage that is:

• Higher than a half-wave rectifier for the same input and firing angle

• Lower than a half-wave rectifier for the same input and firing angle

• Zero

• Always negative

The purpose of the freewheeling diode in a single-phase half-controlled rectifier with inductive load is to:

• Allow reverse current flow

• Prevent back EMF

• Enable continuous current flow when the thyristor turns off

• Reduce voltage spikes