TL494 starts at abt. 7V if I am not wrong. This is just barely legal for end-of-life of zinc-carbon 6F22 (9V) batteries. It also has some of the most temperamental opamps I've ever seen. Not that I am not using it. 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