LED operating point

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Vidhya
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LED operating point

Post by Vidhya » Sat Jun 08, 2002 11:59 am

I have super bright white LED
How I can know the opimum operating point.

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Externet
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Re: LED operating point

Post by Externet » Sat Jun 08, 2002 12:33 pm

Hello.
Check its data sheet. If you do not have it...
If you mean optimum as maximum life, drive it with less than 20 mA. The voltage across it will be around 3.8 V, depending on the manufacturer or composition. If you mean maximum brightness, you could push it up to 40mA.
You cannot have both "optimums"; depends on your application.<p>Miguel
- Abolish the deciBel ! -

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MrAl
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Re: LED operating point

Post by MrAl » Mon Jun 10, 2002 1:11 am

Hi Bank,<p>If you have a white 5mm Nichia or something
like that, then i agree that 20 to 40ma
is best.<p>If you have the advanced high power Luxeon
Star then you have a different story:
1 watt Luxeon Star => 350ma (and about 3.3v)
5 watt Luxeon Star => 700ma (and about 6.8v)<p>The 5 watt model also requires extra heatsinking.<p>
You can read more about LED circuits at:
http://www.candlepowerforums.com/cgi-bi ... =forum&f=6<p>Good luck with your circuits,
Al
LEDs vs Bulbs, LEDs are winning.

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dacflyer
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Re: LED operating point

Post by dacflyer » Mon Jun 10, 2002 8:06 pm

where are these super
1 watt
5 watt LED's found? & $? sounds awsome !<p>i heard also that there is now a purple or ultraviolet led now,, is this true?

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MrAl
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Re: LED operating point

Post by MrAl » Mon Jun 10, 2002 9:45 pm

Hi dacflyer,<p>The 1 watt and 5 watt LED's are made by Lumileds
and are called "Luxeon Stars". They also make other
LED's, but the best one for a flashlight is the LS/o,
which stands for "Luxeon Star With Optics".
The optic is a tiny lens that comes mounted over the LED.<p>I have the 1 watt white model, and even that is very bright
and puts out a lot of light. I power it with a Li-ion
battery in a small flashlight shorter then the minimag and
get about 4 hours run time.<p>The distributor for the LS is Future Active.<p>Here's a link to Luxeon:
http://www.luxeon.com/products/star_index.html<p>I've found that sometimes their links dont work right,
so you may have to go to luxeon.com and search from there for the
"star".<p>The 'emitter' version provides a spread out illumination pattern,
while the 'optics' version provides a tight beam of light.<p>They come in colors too, but i dont follow that too close because
im only interested in the white ones.<p>The price for the 1 watt white model is about $15 each, and for
the 5 watt model about $36 (USD).
The 1 watt model is very much worth the $15.<p>People have already retrofitted an LS/o into a minimag flashlight,
using a circuit called the "ZLT". The ZLT circuit has an efficiency
of about 85% when driven from two AA batteries and used with an LS.<p>
Good luck with it,
Al
LEDs vs Bulbs, LEDs are winning.

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dacflyer
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Re: LED operating point

Post by dacflyer » Tue Jun 11, 2002 3:19 pm

i have a ton of leds from lumi-leds. mostly the 18 led clusters from the LED Traffic lights
the red / yellow / greens. mostly from bad units,, usually the power supplies go belly up, but the leds are still fine,, they look like pills mounted on a heatsink,,very powerful lights,, with some mods, i made a nice pair of trailer light for my trailer 8" round..lol

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