My LED FAQ! This covers many of the questions people ask me. Please read this before e-mailing me. New file 7/4/2001, updated 9/23/2001.
Overview of the different LED types - the different colors, brightnesses, and a bit of the basic chemistry and electrical and other properties of each of these. (Updated 12/13/2000)
"LEDs 101" or "LEDs For Dummies" - how to make them work, why to use a dropping resistor instead of a 2.4 or whatever volt regulator. (Don't laugh until you see what I have seen in sci.electronics.basics!) (Opened to the public 7/16/99, but still under construction.)
The truth of pulsing LEDs to make them appear brighter. The nonlinearity that sometimes makes this work is in LEDs and not in human vision. This usually does not work when feeding 20 mA or more of average current through an ultrabright LED. (new document 12/1/99, updated slightly 6/19/2001)
UV from the right kind of blue LED! Other blue LEDs and blue light sources will get some blacklight effects since many non-blue fluorescent substances fluoresce from some visible light as well as UV. But 450 nM broadband blue GaN LEDs can be made to produce some UV! UPDATED 5/8/2001!
My Yellow SiC LED Page - I managed to get my hands on one of those rare LEDs! (NEW FILE 12/13/2000 minor update 5/27//2000!)
How much you need of red, green and blue LEDs to make white of various color temperatures. Only certain LED types are covered here, and the red one is more than twice as efficient as the usual GaAlAsP "ultrabright red". Even with this great red, you need more red and less blue than you would think! (New file 7/4/2001)
My Blue LED Shootout - to show advantages and disadvantages of popular and less-popular wavelengths of blue LEDs. (updated slightly 9/24/2000)
My page on Organic LEDs, Polymer LEDs and the like. New and still under construction with slow progress - I am mainly following the usual semiconductor kind of LEDs more than stuff sometimes known as "DC electroluminescence".
UPDATE 11/10/2001 - he has acquired "Pro Metric" photometric test equipment and is publishing Pro-Metric" graph results on LED lamps and LED flashlights.
Reduced graphic-frame usage entry to this worldwide-significant page - http://ledmuseum.home.att.net/index2.htm
And note that Craig does lots of updating and more and more frequently than I do. He has more time to test LEDs and to type web material than I do so you should check this site out. There will always be something you can find there and not in my site and maybe nowhere else in the world. Updates continue with no sign of stopping, with yet another significant one noted 11/8/2001 and a significant one of his almost daily updates in the LED flashlight area on 11/9/2001.
http://people.bu.edu/efs/Light-Emitting-Diodes-dot-org/index.html, a site with lots of theoretical info on light emitting diodes, much of it quite technical.
Paul Mathew's LED FAQ - new location.
The White LED Club, of Yohoo Clubs.
The High Brightness LED Page at Compound Semiconductor.
A list of manufacturers of LED and LED products at the Lighting Research Center at the Rensselaer Polytechnic Institute.
The home page of Renssalaer's Lighting research Center - includes links to LED stuff.
NOTE - current upgraded grade LEDs are best-obtained from Nichia sales offices. The ones from surplus outfits are often previous grade (dimmer but still very impressive) even if you confirm the same part numbers. (Nichia is known to improve their LEDs without changing their part numbers.) Or, they may vary strangely in beam width.
NEW - they now have UV LEDs. They have a violet laser diode in production,
although production may be very limited at this early stage.
(updated 2/13/2000)
Straight to Nichia's web site.
Straight to the
web site of Toyoda Gosei, another maker of ultrabright blue,
blue-green, and green gallium nitride LEDs.
Another Toyoda
Gosei upper-level page for LEDs.
Toyoda
Gosei will produce white LEDs.
Toyoda
Gosei news from them as of 4/24/2001 - they will improve the efficiency of
their LEDs.
Toyoda Gosei LED
datasheets at Roithner Laser in Germany (datasheets are in English).
Straight to the web site of Cree, another maker of bright gallium nitride LEDs. But it looks like they stopped making lamps and now just make the dice / chips.
The LED top page of Agilent, spun off by Hewlett Packard.
Lumileds, a joint venture of Agilent and Philips Lighting.
The home page for Lumileds' Luxeon series of high power LEDs.
Toshiba. Hit the "Products List" selector and select optoelectronics.
Ledtronics, a maker of LED products such as indicator lamps and LED screw-in light bulbs.
Straight to the web site of Opto Technology, a maker of miniaturized LED cluster lamps in heat-sinkable TO-66 packages and the like. They also do custom jobs.
Gentex, who makes things such as map lights built into rearview mirrors.
Craig Johnson's list of suppliers, manufacturers, etc. Includes LED products such as brake lights, marine cabin lights and flashlights as well as just LEDs.
Written by Don Klipstein.
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