IR L.E.D. TESTING

[Uriah]

Is there anyway to determine what a loose IR LED is? I know a resistor
has a color code, do IR LED's have any way of determining what their
values are?

 

[Jon Kirwan]

On Wed, 27 May 2009 17:47:13 -0700 (PDT), Uriah <uriahsky@hotmail.com>
wrote:

Is there anyway to determine what a loose IR LED is? I know a resistor
has a color code, do IR LED's have any way of determining what their
values are?

LEDs generally emit over a fairly wide bandwidth. It has been a long
time, but the FWHM is on the order of 100nm in the visible/near
visible. So there isn't a precise value, anyway. It's pretty broad,
generally speaking. As far as markings go, I'm not aware of any
widely accepted practices. If it were important to me and I didn't
have expensive equipment at hand, I'd use a DVD-RW disk canted at an
angle in a cardboard box with a narrow slit cut in it with a razor
blade and an opening through which a cheap digital camera would take a
photo (the pixels are often sensitive in the near IR, unlike our
eyes.) Looking at the digital picture would tell me a lot and cost
about a dollar for the materials not counting the camera.

Jon