At 11:26 AM 10/27/2011, Bob Blick wrote: >On Thursday, October 27, 2011 10:26 AM, "Wouter van Ooijen" wrote: > > > 4. a typical 'it works on my desktop' circuit. If I found myself workin= g > > for a company that put this in a product I would run, emigrate, and get > > a new name. > >Best comment I've seen in over a week, I'm in total agreement with you. I first agreed with you, but taking a much closer look at the circuit=20 reveals that it is actually a pretty cool design, given the stated=20 working conditions. 1) Vdd =3D 7.4Vdc. 6 NiCd or NiMh cells have a reasonably flat=20 discharge curve - by the time the battery voltage decays to around=20 7V, there is only a few percent of charge left in the cells. 2) Vcontrol =3D 0V, float, 5V. These are nicely defined voltage levels=20 that actually do as they are supposed to do. My only change would be to add a resistor from the output of the=20 bottom half-bridge to the center of the LED chain that controls the=20 top chain instead of the direct connection that is currently there. As I mentioned in my previous post, this is something that I would=20 not design myself. But I can't really fault the design - it does=20 exactly what it is supposed to do at very low cost under the very=20 specific conditions that were stated (Vdd =3D 7.2 - 7.4Vdc). Don't=20 ever try to use it with any other supply voltage - it either just=20 won't work or it will generate smoke. dwayne --=20 Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax www.trinity-electronics.com Custom Electronics Design and Manufacturing --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .