DIYbanter - View Single Post - Why aren't many / most LED light bulbs dimmable?

Jim Yanik

" 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.

hey,they were FREE,including the batteries. ;-)
HF gives them away free with a coupon from their many ads.

of course,they don't use the batteries efficiently.

--
Jim Yanik
jyanik
at
localnet
dot com