Hi guys, i came across the turning on process of thyristor scr and i am pretty confuse about what my lecturer says, he says that when a gate current is applied the depletion region of the j2 will be increased and this causes regenerative effect and large anode current to flow

But i was confused, doesnt the increased depletion region impede current flow from anode to cathode?

 

Sounds confusing to me!

It might help you to read this:-
http://en.wikipedia.org/wiki/Thyristor