How does an LED work?

Brasso

Brasso

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OK, OK. I don't expect an explanation here, but if someone could direct me to a website where it is explained in terms someone who doesn't have an EE degree can understand I'd be appreciative. Thanks.
 
Brasso

Brasso

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Thanks. Those helped out quite a bit for a basic understanding.
 
chevrofreak

chevrofreak

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I've been getting my info from How Stuff Works for years, its a pretty decent resource.
 
The_LED_Museum

The_LED_Museum

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From my website, comes this text:

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LEDs (Light Emitting Diodes) are those little colored lights you see in electronic equipment, household appliances, toys, on signs, and many other places. Red, yellow and green ones are the most common, since they have been around the longest. Other colors, like turquoise, blue, pure-green and white are much newer, so you may not see many of them around yet. But you will.
LEDs are different from ordinary light bulbs because they do not have a filament to break or burn out. They generate very little heat, and are ideal for putting lights into battery-operated equipment like telephones, toys, and portable computers.

An LED is basically a really fancy diode. Diodes only let current (electricity) to flow in one direction and not the other. LEDs are diodes too, but they have the unique "side effect" of producing light while electricity is flowing through them.

In the simplest terms, an LED is made with two different kinds of semiconductor material: one type that has too many free electrons roaming around inside, and another that doesn't have enough. When an electron from one material (the donor) gets pushed across a thin barrier and gets into tiny spaces in the other (the holes), a photon or particle of light is produced.
The color of light depends on a number of factors, including the type of material they make the LED with and the material's quantum bandgap (how much energy each electron needs to pack in order to cross the barrier).
A smaller bandgap that fairly weak electrons can cross gives you infrared or red light, while a large bandgap that needs really strong electrons gives you light that has a blue or violet color to it.

Things that go on inside of an LED are a little more complicated than this, but you get the idea.

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powernoodle

powernoodle

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The best answer may be that no one really knows how an LED works. The biggest brainiacs in physics and quantum mechanics and all of that good stuff don't even begin to know what a photon is, much less how it is emancipated from its source. We are to quantum physics what Medieval bloodleters are to contemporary neurosurgeons - pretty clueless. /ubbthreads/images/graemlins/smile.gif

best regards
 
PhotonWrangler

PhotonWrangler

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That reminds me of a parallel response in the field of medicine. I've seen so many cases where new medicines were introduced, and in particular when new psych meds were announced, when they'd say "we don't really know how it works."

So how come we're able to manipulate these things and obtain positive, predictable results when we don't understand just what the heck is going on?
/ubbthreads/images/graemlins/thinking.gif /ubbthreads/images/graemlins/yellowlaugh.gif
 

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