Question

Consider the two transistor analogy of SCR, if α1 & if α2 are the common-base current gains of both the transistors then to turn-on the device

(a) α1 +  α2 should approach zero

(b) α1 x  α2 should approach unity

(c) α1 –  α2 should approach zero

(d) α1 +  α2 should approach unity

The question was posed to me in an internship interview.

This key question is from Thyristors-4 in portion Power Electronics Devices of Power Electronics

Answer 1

Right option is (d) α1 +  α2 should approach unity

Explanation: To turn on the device sum of both the current gains should approach unity value.