Thanks for the links. I'm in the process of trying to build the circuit, but oddly, the multimeter just keep rising towards zero fairly fast. It start at around -7v and just keeps creeping up to 0v ... I must have a bad capacitor or something. I think I'll try to accomplish the negative voltage using the MAX233 since I have a few spares sitting around anyway. I wonder if I can stick a regulator on the output without drawing too much current. Stupid me, I ordered 7905 instead of 79L05 (or whatever that smaller one is). I'll give it a shot, worst that can happen is I burn up a sample. Thanks for the info guys...Peace MJ Brush ----- Original Message ----- From: "marco.genovesi@libero.it" To: Sent: Wednesday, May 19, 2004 6:25 AM Subject: Re: [EE:] Simple Voltage Inverter Mattew, a brief google search "555 negative voltage" give me these links (are similar circuits but some are better explained): http://ourworld.compuserve.com/homepages/Bill_Bowden/page10.htm http://www.csgnetwork.com/ne555c1.html http://www.smoke.com.au/~ic/neg-volt-gen.html http://www.newstead.tased.edu.au/oldweb/curriculum/Electronics/Advanced/sect6.htm ............ ............ The 555 is a bit noisy, use CMOS version if you don't need highest current otput regards Marco ---------- Initial Header ----------- From : "pic microco -- 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