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Topic: Hot LEDs (Read 2281 times) previous topic - next topic

Grumpy_Mike

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Your finger perceives that radiation as heat

No they don't not at those sort of wavelengths, you fingers peeve them just the same as if they were visible light.


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Your finger perceives that radiation as heat

No they don't not at those sort of wavelengths, you fingers peeve them just the same as if they were visible light.


I beg to differ, Mr. Grumpy!  Typical IR LEDs emit around 940nm and that is used extensively in the medical industry because it does penetrate the skin.  Here's some light reading for you:

http://labs.seas.wustl.edu/bme/wang/epub/2004TD-PMB-Thermal.pdf

Grumpy_Mike

You will notice that the title of that paper says:-
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a theoretical investigation

Have you ever stuck your finger in front of an IR LED? Have you felt it get hotter? Was this hotter than when the same power was given off by a red LED?
Perception is everything in this question.

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