Measuring IR LED Flux!

MikeLip · Aug 22, 2005

OK guys, if this is the wrong forum, point me to another place! We use infrared LEDs to illuminate a pattern of reflective stripes on a rotating disc we use as a tachometer. I seem to be running into a problem of reduced LED output after a few thousand hours of continuous operation, and this results in missed counts from the tach. I would like to verify this with empiric measurements, and do it on a shoestring. Is there a sensor that I can simply plug into a DMM to obtain relative outputs?

HarryN · Aug 22, 2005

One of the techniques that the pro's use to measure light of any wavelength is with temperature rise of the target.

It might be possible for you to set up some kind of test stand with a black Al target and a temp probe. Isolating the waste heat of the LED from the target, as well as insulating the target to avoid rapid loss of the heat are important.

I think Si solar cells at R/S might also work.

Doug Owen · Aug 22, 2005

Sure there is. Several come to mind. First and maybe easiest is the detector you're already using......

Next would be a CdS cell hooked to your ohm meter (I just tried it....)

PM if you can't sort it out.

Doug Owen

Measuring IR LED Flux!

MikeLip

Flashlight Enthusiast

HarryN

Flashlight Enthusiast

Doug Owen

Flashlight Enthusiast

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