optoisolator testing question

Discussion in 'General Electronics Chat' started by 1-3-2-4, May 26, 2013.

  1. 1-3-2-4

    Thread Starter Active Member

    Dec 26, 2008
    194
    1
    I was following this and I ran into something that does not match up on my end..

    http://preher-tech.com/documents/optoisolators

    Testing the anode and cathode passed but everything including testing it the reverse way I don't see on my end.

    I tried the 2nd method and nope still nothing, the 2nd way I assume it would cause the resistance to stop but nope I still see OL on my meter.
     
  2. nigelwright7557

    Senior Member

    May 10, 2008
    487
    71
    Putting power to the LED will switch on the transistor.
    You need to power to the transistor through a resistor to see it working.
     
  3. 1-3-2-4

    Thread Starter Active Member

    Dec 26, 2008
    194
    1

    Turns out my other meter was not supplying enough power to turn the LED on.. but yeah they work fine :mad:
     
  4. LDC3

    Active Member

    Apr 27, 2013
    920
    160
    If your multimeter is powered by a 1.5 V battery, it may not be enough voltage to get the same readings as on the document.
     
    1-3-2-4 likes this.
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