On Mon, 27 Dec 2010 07:09:29 -0600, Jim Yanik wrote:

" wrote in
:

On Sun, 26 Dec 2010 12:02:15 -0600, Jim Yanik wrote:


Probably parallel strings of LEDs.

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


I meant several series strings -in parallel-.

curiously,some free Harbor Freight 9 LED flashlights I have have all 9
LED's in parallel,and no current limiting resistor,depending instead on the
internal resistance of the 3 AAA cells.

That's a current-sharing nightmare waiting to happen. I suppose the LEDs are
all from the same batch, so at least in theory, it works. ...well enough for
cheap Chinese junk, anyway.

Thinking about it a little, the temperature coefficients are in the right
direction so at least the thing isn't going to run away.