Question

1. the scr is turned on by

a. gate voltage.
b. increasing anode voltage.
c. reducing anode voltage.
d. forced commutation.

Explanation:

A Silicon - Controlled Rectifier (SCR) is a thyristor which is turned on by applying a positive voltage to its gate terminal with respect to the cathode. This positive gate voltage triggers the SCR to conduct current from anode to cathode. Increasing or reducing anode voltage alone does not turn it on in the normal sense as the gate signal is the key for triggering conduction. Forced commutation is used to turn off an SCR, not turn it on.

Answer:

A. gate voltage