Question

For the following RC triggering circuit with R load and a firing angle of α, the voltage across the SCR (thy2) will be zero for

(a) ωt = 0 to α & ωt = π to 2π+α

(b) ωt = 0 to π

(c) ωt = α to 2π

(d) ωt = α to π

This question was addressed to me at a job interview.

Question is from Firing Circuits-3 topic in section Other Circuits of Power Electronics

Answer 1

Right option is (d) ωt = α to π

Easiest explanation: The SCR is triggered at α therefore voltage appears across the load from ωt = α to π only as in case of a half wave firing circuit the SCR is naturally commuted at π.