Thyristor & Power Control Circuits Unit 3 – SCR DC Control
Exercise 2 – SCR Control of a Half-Wave Rectifier
EXERCISE OBJECTIVE
When you have completed this exercise, you will be able to demonstrate how an SCR controls a
half-wave rectifier by using a typical half-wave rectifier circuit. You will verify your results with
an oscilloscope.
DISCUSSION
- This circuit uses an SCR to control a half-wave rectifier.
- Closing S1 triggers the SCR; it remains on because R3 supplies the holding current during
the negative half-cycle of Vac. - While SCR conducts, CR1 acts as a half-wave rectifier because the load current flows
through R4 on the positive half-cycle of Vac. - Turn the SCR off by removing the holding current; this is achieved by opening R3.