Russell, An excellent treatise on the problem - some points of which I had already thought through, others not. At this stages I am locked into a particular relay, and the spec sheet says it will turn off fast enough for this application(2mS), just doesn't say how that is accomplished! I am switching 12 amps, so light duty fast reed relays aren't being tried. My switch can tolerate quite a high pulse, so I think we can probably eventually come up with something that will create a rather large pulse but shut this thing down fast enough. Off to the lab! -- Lawrence Lile Senior Project Engineer Toastmaster, Inc. Division of Salton, Inc. 573-446-5661 voice 573-446-5676 fax -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads