Do LEDs generate heat?

[0810]

im looking into buying a new 12cm case fan.. led or no led? like all lights, dont they generate heat? i mean, even christmas lights get warm after sometime, shouldnt leds?

 

[Skin]

leds give out a VERY small amount of heat. I wouldnt think you could even measure a difference in temps.

 

[Troney1169]

While they do generate heat it would take about 20-50 or even more LEDs to make any noticable change in temps ina case. And xmas lights heat up quite quickly.

 

[jpmkm]

LEDs, as with all semiconductors, do indeed produce heat. However, in this case it will be completely insignificant. BTW, there is a big difference between christmas lights and LEDs. Christmas lights are incandescent whereas LEDs are semiconductors. Unless, of course, you are talking about LED christmas lights.

 

[Elledan]

A typical LED is 5 V at 20 mA, or 100 mW. If that worries you, there are also low-current LEDs which are around 2 V at 2 mA, or 4 mW

 

[Majin]

im looking into buying a new 12cm case fan.. led or no led? like all lights, dont they generate heat? i mean, even christmas lights get warm after sometime, shouldnt leds?

Light Emitting Diodes are different then a normal light.
A Incandescent light creates light by passing electrical current across a thin wire (filament). This causes the filament to heat up and glow. Thus creating large amounts of heat and Light.

LED’s do not require large amounts of current because, they are illuminated solely by the movement of electrons in a semiconductor material known as a Diode.

 

[Elledan]

Light Emitting Diodes are different then a normal light.
A Incandescent light creates light by passing electrical current across a thin wire (filament). This causes the filament to heat up and glow. Thus creating large amounts of heat and Light.

LED’s do not require large amounts of current because, they are illuminated solely by the movement of electrons in a semiconductor material known as a Diode.

Eh, the reason why incandescents need so much current compared to LEDs and fluorescent light is because only around 5% of the energy which goes in comes out as light (visible part of the electromagnetic spectrum), hence incandescents require like 19 times more current than a device which converts 100% of the ingoing current to light.

What this means is that lightbulbs are a lot more useful as spaceheaters than as lightsources, and even then they're quite wasteful.

 

[ninethreeeleven]

I remember reading somewhere (Pop Sci I think) that the only thing holding back LED spotlights is heat. The article said that you need about 200 LEDs in a very small space (not convential computer light LEDS) and they would just melt each other. One company in the article got around this, but it was pretty expensive and not practicle.

If anyone knows what I am talking about please respond.

And I say they were not conventional because it was a "disk" of LEDs that produvced the light. It resembled a silicon waffer with the chips on it.
Sort of like this.

 

[Elledan]

I remember reading somewhere (Pop Sci I think) that the only thing holding back LED spotlights is heat. The article said that you need about 200 LEDs in a very small space (not convential computer light LEDS) and they would just melt each other. One company in the article got around this, but it was pretty expensive and not practicle.

If anyone knows what I am talking about please respond.

And I say they were not conventional because it was a "disk" of LEDs that produvced the light. It resembled a silicon waffer with the chips on it.
Sort of like this.
http://www.iupload.net/072005/siliconLEDLookAlike.jpg[IMG][/QUOTE]
You mean like the Luxeon Stars? These LEDs require heatsinks to keep them from melting :)