one advantage LED has over incandescents is that..

it runs cool...

or is it?

i read thru several luxeon threads in this forum and i do notice things like heat sinking and even a fan to lower down the heat produced by the LED.

isnt LEDs supposed to be cooler than incandescents?
or is it?

what makes luxeons run hot?

thanks! /ubbthreads/images/graemlins/smile.gif

Re: one advantage LED has over incandescents is th

Leds radiate heat through the connection to the die itself mechanically while incandescents radiate heat through light and heating up the glass itself some. You can touch an LED that is running while an incan after awhile will burn you because of this. The amount of heat radiated is a function of efficiency. LEDs are mostly more efficient than average incans thuse they radiate less heat, but high wattage luxeons still need to get rid of the heat they generate because they are not 100% efficient... more like 15-25% and as technology improves this will improve also meaning less energy wasted as heat.

Re: one advantage LED has over incandescents is th

Or, in other words, incandescent lights shed most of their heat as infrared emissions that (mostly) pass through the bulb and into their immediate environment. LEDs emit zero infrared radiation (unless they're IR LEDs), so the heat remains localized in the LED die.

Even low-power LEDs generate heat. The average "superbright" green/blue/white 5mm LED is dissipating about 70mW - not much compared ot a 3W or 5W LED, but it's notisable after a few minutes of continuous operation. Get a bunch of them together and it's a bit more noticable.

Re: one advantage LED has over incandescents is th

How about those big arrays that they use in traffic signals or in automobile taillights? I realize the traffic signals don't stay on for a long time but there have a bunch of LED's in there. In the case of an automobile, the taillight (not stoplight) can stay on for hours at a time during night driving.

Re: one advantage LED has over incandescents is th

i have this one torch with 9 non luxeon LEDs.

it gets warm after a while but actualli gets down to room temperature after half an hour..

isnt that odd?

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idleprocess said:
Or, in other words, incandescent lights shed most of their heat as infrared emissions that (mostly) pass through the bulb and into their immediate environment. LEDs emit zero infrared radiation (unless they're IR LEDs), so the heat remains localized in the LED die.

Even low-power LEDs generate heat. The average "superbright" green/blue/white 5mm LED is dissipating about 70mW - not much compared ot a 3W or 5W LED, but it's notisable after a few minutes of continuous operation. Get a bunch of them together and it's a bit more noticable.

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