optocoupler getting warm

Discussion in 'General Electronics Chat' started by edmundopt, May 31, 2012.

  1. edmundopt

    Thread Starter Member

    May 4, 2011
    60
    0
    Hello

    I've run into one of my optocoupler getting warm(about 30º Celsius), I will not post a schematic because it fairly simple:

    Optocoupler TLP621 (marked GB)
    input for LED = 5v, about 15mA(330ohm resistor 5%)
    output for photo transistor 12v and about 2mA

    I'e unsoldered the optocoupler, placed into a breadboard, and used 270ohm resistor (because I've run out of 330) resistors on the 5v side, I was surprise because it runs cool.

    What I'am missing here, does the temperature diference is because of saturation of the photo transistor? should I increase the amount of current being transmited into the optocoupler to get it cooler, ou decrease the photo transistor current ?

    regards and keep up this great forum
     
  2. tracecom

    AAC Fanatic!

    Apr 16, 2010
    3,871
    1,393
    A schematic would be helpful. What is limiting the photo transistor current to 2mA?
     
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