On Sat, 14 Dec 2002, David & Ann Scott wrote: *>But I've used a 1uF capacitor in RM's circuit - which blinks at about 1-5 *>Hz. This is my frequency isn't it? Not quite. If you refer to the core, it has to do with the switching frequency, not with the blink frequency. I hope that I understood what you asked ... Peter -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics