James Newton wrote... >I suppose it is Rube Goldberg'ish to some degree, but it sure worked = will >for him! It's a crusty old guy trick. (no offense Dave) People keep telling me I'm getting crustier with each passing year, and I'm old enough that I've done commercial products with vacuum tubes (back when you sometimes HAD to use them; not this modern-day stuff designed for Tube Cult audiophiles who stare in fascination at the glowing filaments) and I got my first embedded-systems experience on the Intel 4040 (a batch controller for a concrete block plant); so I guess I'm a "crusty old guy". No offense taken. "Rube Goldberg'ish", though, is an attribute usually given to something which is outrageously- indeed comically- complex and roundabout. This thing has only three working parts (and it responds to true RMS, to boot!) so it ain't exactly complex. Yeah, it's unusual, perhaps you could call it unorthodox; but not "Rube Goldberg'ish". It's not original, either, as I've seen circuits using a CdS cell in that fashion as part of a lamp power regulator years ago. Cheers, Dave -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.