You know, there would never be all of this conversation if MOSFET's were used. They are so much simpler, especially for this switching application. Cliff ----- Original Message ----- From: "Alan B. Pearce" To: Sent: Thursday, January 10, 2002 9:17 AM Subject: Re: [PIC]: Re: PIC control of PIC power supply >In this application I would >probably go for a darlington pair Be very careful trying to saturate a darlington transistor, as the saturation voltage is at least one Vbe (for the second transistor) + the Vce of the first transistor. When trying to do this make sure the two transistor collectors are not connected together by using separate discrete devices. Think about the internal circuit of an integrated device. -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body