At 11:30 AM 5/21/00 -0500, Jim wrote: >How 'bout an "SCR" - > >Once 'fired' it is on till power is removed ... > >SCR a three terminal device: Anode, Cathode and Gate. > >Postitve (current limited) voltage applied to >Gate wrt Cathode and the device will conduct >from Anode to Cathode. > >SCR is 4-layer NPNP device "configured" internally >as a pair of transistors that keep each other on once >turned on. You can also use a digital "flip-flop" or "latch". Obviously also, the SCR mentioned could be constructed out of two discrete transistors to match a transistor latch. ================================================================ Robert A. LaBudde, PhD, PAS, Dpl. ACAFS e-mail: ral@lcfltd.com Least Cost Formulations, Ltd. URL: http://lcfltd.com/ 824 Timberlake Drive Tel: 757-467-0954 Virginia Beach, VA 23464-3239 Fax: 757-467-2947 "Vere scire est per causas scire" ================================================================