At 04:11 PM 6/24/2004 -0500, llile@SALTONUSA.COM wrote:

>If you put a 5v 78L05 regulator across a resistor, it becomes a constant
>current device.  A pretty cheap way of doing it, maybe easier to get than a constant current diode.  You get the constant current, IIRC, out of the ground pin with the resistor connected between the ground pin and 5V pin.

The LM317 and LM338 do it with lower voltage drop, since you can set it to 1.2V output. I think that's also a band-gap voltage. They are VERY flat with temperature, I use these for my NIMH battery station, on the dischargers.
They get pretty hot, dumping 7-14W each, but they remain flat.

IIRC, they make similar devices up to about 10A.

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads