Failure of Multi-color LEDs?

Discussion in 'General Electronics Chat' started by mapleleafs, Mar 17, 2010.

  1. mapleleafs

    Thread Starter New Member

    Mar 16, 2010
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    0
    Hello All,

    I just have a simple question regarding multi-color LEDs.

    Is it possible for just a single color from within one of these LEDs to stop functioning? Or rather, when these LEDs fail, will all colors stop displaying?

    Thanks,
     
  2. retched

    AAC Fanatic!

    Dec 5, 2009
    5,201
    312
    Yes, one can fail. If you have a red and blue 2 color LED, each color still has a separate cup, and separate Vf. If you give the same power to both, the red will burn out before the blue.

    If they are common cathode and the cathode fails, all will stop working. Same with common anode.

    In common cathode, if an anode fails, the others will work. and vice-versa with common anode
     
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  3. mapleleafs

    Thread Starter New Member

    Mar 16, 2010
    8
    0
    Ah I see. Thanks for the quick reply.
     
  4. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    I have a few 3-colours solar garden lights. The RGB LED has a built-in fading IC that fades from red to green to blue over and over. One of the LEDs had its blue LED or driver fail.
     
  5. hondabones

    Active Member

    Sep 29, 2009
    123
    1
    I agree with retched, each color is rated approximately at the normal values for those LEDs. Blue is usually 3.5 volts or so red is 2.8, yellow is like 1.8 the data sheet can give you a better operating voltage to allow the maximum efficiency from the LED.
     
  6. Audioguru

    New Member

    Dec 20, 2007
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    Blue is 3.2V to 3.6V, red is 1.8V to 2.1V and yellow is made with red plus 3.2V to 3.6V for new bright green. Old dim green LEDs were about 2.4V and old dim yellow LEDs were about 2.2V.
     
  7. hondabones

    Active Member

    Sep 29, 2009
    123
    1
    Yep, that sounds right. I was basing it on the LEDs I have in my toolbox. (just estimating the voltages)
     
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