Check out this link for an explanation of how an SCR works.


http://www.allaboutcircuits.com/vol_3/chpt_7/5.html
The Silicon-Controlled Rectifier (SCR) - Chapter 7: THYRISTORS - Volume
III - Semiconductors




Chuck



Offbreed wrote:

Well, yes, that can be a problem, but I think SCRs can be shut off by
changing the bias of the gate circuit. ...