555 timer trigger circuit

Discussion in 'The Projects Forum' started by edneil_allaboutcircuits, Oct 24, 2010.

  1. edneil_allaboutcircuits

    Thread Starter New Member

    Oct 24, 2010
    1
    0
    I configured my 555 timer to be used as a monostable multivibrator. Now the thing is, I don't know how to construct a trigger circuit that will input a 2V (with a 1us pulse width) signal to the trigger pin of my 555. Can somebody help me find a way out?
     
  2. mbohuntr

    Active Member

    Apr 6, 2009
    413
    32
    555's use a dropout pulse to trigger the output because the trigger pin uses a pullup resistor.(held high) See Bill Marsden's 555 section and circuits, they really helped me. Try a 2n2222 open collector on the trigger.
     
  3. Wendy

    Moderator

    Mar 24, 2008
    20,764
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