Re: How to drive High Power Infrared Led - Epitex L940-66-60


Barry Cense wrote:
redbelly wrote:
The resistors can stand a lot higher temperature than we can. Will it
be somewhere that people are likely to touch it? If not, I wouldn't
worry about it; you're below 1/2 the rated power.

Mark

A rule of thumb (no pun intended) is that when a surface is above 41
degrees Centigrade, we feel pain when we touch that surface with our
fingers. Obviously, this only holds for materials with a heat
conductivity coefficient that is not too exotic.

Barry

Hi Barry.

Okay, let me think just a minute. Twice 41 is 82. Subtract off 10% to
get 74 (to the nearest degree). Now add 32 to THAT and we get 106
degrees Fahrenheit.

Yep, 41 C sounds about right.

I'm a nerdy type who likes to measure common everyday things. I once
determined that the hottest bath water that is still comfortable is
around 101 or 102 F (for me, anyways; YMMV). That's 38 to 39 C.

Mark

p.s. What's a non-exotic thermal conductivity in your book? I'd say
between 1 and 30 W/K-m, or thereabouts.

.