Help with a basic circuit for protection

Discussion in 'Digital Circuit Design' started by samslack, Oct 12, 2016.

  1. samslack

    Thread Starter New Member

    Oct 11, 2016
    4
    0
    Hello all I have a strange arcade type pinball machine that I am playing with. I need to take a 11.64 V dc pulse that it outputs to a simple optoisolator

    This pulse is no more than 50ma I am looking for a good opto isolator that will trigger. I have tried a few and can get it to work on a bread board using higher current using NTE 3098 but it seems that they draw or need too much current to trip them.

    Any suggestions on an opto isolator that will only draw 20 ma.
     
  2. Sensacell

    Well-Known Member

    Jun 19, 2012
    1,129
    266
    How are you connecting it up?
    What are you controlling on the other side of the coupler?

    You must use a resistor in series with the LED to limit the current.
    If you use a 1000 ohm resistor, it will draw 10 ma from your source.

    The output current will not be greater than about 10 - 60 ma., maximum. (Current transfer ratio, from data sheet)
     
  3. samslack

    Thread Starter New Member

    Oct 11, 2016
    4
    0
    So the other end is a counting / scoring device it counts by contact no voltage applied when you short to wires it increases the count by one . I want to make the pulse from the pinball machine to click the counter.

    On the pinball output I connect the pos output 11.63 vdc to a 150ohm resistor leg the other leg goes to the anode of the nte3098 optoisolator the cathode connects to common on the pinball output. This is where I have measure the 11.63 v from it pulses for a sec. The other side just makes contact to count the counter. No voltage runs through it.

    Im guessing there is not enough current to grip the optoisolator
     
  4. samslack

    Thread Starter New Member

    Oct 11, 2016
    4
    0
  5. samslack

    Thread Starter New Member

    Oct 11, 2016
    4
    0
    Here is the data sheet
     
  6. crutschow

    Expert

    Mar 14, 2008
    13,005
    3,232
    But current does.
    What exactly is the current of the counter when it is shorted to make the count?
    You can measure that with a multimeter set to the current range.
     
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