IR LEDS colors - what's the difference

Discussion in 'General Electronics Chat' started by sharkfire, Mar 1, 2008.

  1. sharkfire

    Thread Starter Member

    Feb 13, 2008
    What's the difference between the clear IR LED, the Blue, and the Ultra Blue(is that what it's called).

    And how far can it send IR Pulses, what degree?
  2. thingmaker3

    Retired Moderator

    May 16, 2005
  3. scubasteve_911

    Senior Member

    Dec 27, 2007
    For an IR emitter, you need to worry about three main specifications when using for a distance. #1) Wavelength #2) Power Rating #3) Emitting Angle

    You first must decide at what distance you wish to make it usable. If this is for a small object detector, you want to get the tightest possible beam angle. Then, you calculate the power that will be present upon the surface of your detector. This is a function of total emitted power and the beam divergence. Next, you must make sure that your photodetector is matched to your emitter's wavelength. If you use a photodiode, you will be given a specifications in Amperes/Watt. With this, you can see how much current will flow at the distance you wish to use it. You can use an appropriate transimpedance amplifier set to the gain needed for your output to be useable.