ATM: LED flashlight conv.

[barry.klein@deltronix.com (Barry Klein)]

Responding to Richard's comments about LED's:
The 30ma rating is typically the max. power for the led.  You don't
really need to drive the bright ones that hard.  For many uses 5-10ma
is fine - and that is a heck of a lot less than a flashlight bulb takes.

If you really want to get esoteric and strive for efficiency you might
want to check into a newsletter just for cave explorers called Spelionics.
Available from:

NSS Communications & Electronics Section
P.O. Box 5283
Bloomington, IN   47407-5283

Also spelionics listserv at: spelionics-request@altadena.net
(haven't tried it)

I just got issue #21.  They have several high efficiency circuits for
LED's as well as incandescant and fluorescant lights.  Other sources for
ideas include Maxim and Linear Technology's application notes.  They
both make some high efficiency switching supply IC's that can be used
as drive circuits.  For led circuits be sure to investigate high-candela
parts from Hewlett Packard, Stanley, and others.  These get so bright they
hurt your eyes.  I would think that at some point the brightness of these
led's defeat the purpose of having a light source that doesn't affect your
seeing (visual purple or whatever...).  I'd be interested to read your
thoughts on this as you can make some damn bright sources with these led's.

Barry

... Elect. Music, Photography, Bubble Machines, Stunt Kites, Elect. Design

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