On Mon, 27 Dec 2010 07:15:08 -0600, Jim Yanik wrote:

" wrote in
:

On Sun, 26 Dec 2010 16:02:42 -0500, wrote:

On Sun, 26 Dec 2010 12:41:26 -0600, "
wrote:

Probably parallel strings of LEDs.

*Series* strings. Parallel does nothing but cause more trouble. ;-)

OK the science comes fast around here
I took a flashlight apart.
It appears they use a 4.5v LED, 9 in parallel with NO resistor at all.
The internal resistance of 3 AAA cells seems to be the limiter

I've seen that too; a very poor design. There is nothing to
current-share across the LEDs. Counting on the internal resistance of
a battery is really ****-poor.

With just the batteries in there the lights are pulling about 244ma
(they are fairly new batteries)
This is hurt your eyes bright.
I put my 1k pot in there and even all the way off I am dropping .05v,
current around 211ma.

I assume you mean, "all the way *ON*", as in "zero" ohms (the wiper
resistance is about 1/4ohm).

don't forget the meter resistance,too.

Oh, certainly. Good catch.