At 04:39 PM 3/20/2008, Bob Axtell wrote: >I haver been screwing around and now the boss wants to go with >the smarter chip, since it has a 2C tolerance, which is 1% or so, >well within our needs. It will >save us a couple of hours, methinks OK - one last suggestion for a method of avoiding Maxim: National makes some pretty good 2-wire temperature sensors, both Voltage and Current styles. Voltage output (acts like a temperature-sensitive zener diode) is probably NOT a good choice because of the IR losses in the battery pack ground wire. Too easy for ground shift to occur. But a 2-wire temperature-sensitive current source: that might actually work pretty good. Power it from the battery pack + lead so that you can use a ground-referenced load resistor. I don't have part numbers handy right now but I can check my notes from projects that I've done in the past. I also suspect that a commodity part from National Semiconductor will be WAY less money than Maxim. dwayne -- 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 -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist