Thyristor & Power Control Circuits Unit 4 – SCR AC Control
UNIT 4 – SCR AC CONTROL
UNIT OBJECTIVE
At the completion of the unit, you will be able to demonstrate ac control of an SCR by using
half-wave and full-wave phase control circuits.
UNIT FUNDAMENTALS
A phase control circuit controls the SCR conduction angle. The SCR conduction angle of a full-
wave phase control circuit is shown. A phase control circuit can also be used with a half-wave
rectifier.
This circuit is a half-wave SCR phase control circuit. Power to the load (R8) can be controlled
during the positive half of the input cycle.