(Jay)
shared these priceless pearls of wisdom:

-I think someone may have already pointed this out, and maybe I didn't
-make it as clear as I should have... I stacked the forward drop of
-MULTIPLE LEDs up until I got somewhere near the bottom end of the
-supply voltage. So for the example I gave, I got to 4 LEDS in series.
- Why waste all that power as long IR (heat) off a big resistor when we
-want red and green light right?

And as somebody else has pointed out, running a series string close to the
bottom limit of Vcc and hoping that a single resistor will provide constant
current to these devices will cook them when Vcc rises to the charging voltage.

No designer in his right mind would use a circuit in this manner.

Jim


Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com