wrote: > So therefore I don't see why you think I'll lose an entire volt in the > lowside driver. I'm thinking 100 mV tops. But please enlighten me. The Darlington connection prevents the second transistor in the pair from saturating. The combined collector connection must always be at a voltage high enough to supply current through the first transistor to the base of the second transistor, which is Vce(sat) of the first + Vbe of the second, which usually works out to about a volt. -- Dave Tweed -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist