An equivalent circuit of a SCR, also known as a thyristor.
SCRs main use in circuits is for AC phase control, as manipulation of the gate will dictate when the SCR will conduct. These are often found on motor control circuits
An SCR, like a diode rectifier, will only conduct half of the wave. In power applications, this will mean only 50% of the power is conducted. To achieve full power conduction, a TRIAC should be used instead.
The triggering circuit used here is typical for simple SCR applications, though it will only conduct a maximum of about 90 degrees. A DIAC placed at the gate to rise the gate voltage before triggering will raise the conduction angle.
To manipulate the conduction time, adjust the second resistor in the triggering circuit.
