The SCR would be turned OFF by voltage reversal of applied anode-cathode ac supply frequency of :
- 10 kHz
- 10 Hz
- 5 Hz
- 5 kHz
Answer: 4. 5KHz
For inverter grade SCR, typical turn off time (toff) is 5 to 50 μsec
For converter grade SCR, turn off time = 50 to 100 μsec
Supply frequency of 5 kHz will turn off the SCR by voltage reversal, because
(1/ 5000Hz) = 200 μsec.