Voltage Rise Detector

Discussion in 'The Projects Forum' started by AnimeChickLover, Mar 21, 2013.

  1. AnimeChickLover

    Thread Starter New Member

    Nov 2, 2009
    6
    0
    I am currently trying to create an circuit which will emit a pulse when the input voltage is increased from 0 to a non-zero value.
    I remember learning about a circuit which does this in the past but my memory has gone completely blank.

    Could anyone help me?

    Thank you
     
  2. MrChips

    Moderator

    Oct 2, 2009
    12,446
    3,362
    This is impossible. You have to define what you mean by non-zero value.
     
  3. AnimeChickLover

    Thread Starter New Member

    Nov 2, 2009
    6
    0
    Sorry bout the bad question,
    What i meant was when a constant Voltage of around 5V is introduced into the input.
     
  4. MrChips

    Moderator

    Oct 2, 2009
    12,446
    3,362
    Much better. You can use an analog comparator that compares two voltages, the input voltage and a reference voltage. You can set the reference voltage to any appropriate voltage, 4V for example.
    When the input voltage exceeds the reference voltage, the output of the comparator will change its logic state, 0 to 1, or 1 to 0, depending on how you connect the pins.
     
    AnimeChickLover likes this.
  5. AnimeChickLover

    Thread Starter New Member

    Nov 2, 2009
    6
    0
    Thank you for the reply,

    Is there any possible methods to change the output of the comparator into a pulse instead of a constant value?
     
  6. MrChips

    Moderator

    Oct 2, 2009
    12,446
    3,362
    Yes. Such a circuit is a monostable multivibrator. You can also take the derivative of the output using a differentiator or a high-pass filter.
     
    AnimeChickLover likes this.
  7. AnimeChickLover

    Thread Starter New Member

    Nov 2, 2009
    6
    0
    Thank you so much!
    Ill go have deeper looks into monostable systems
     
Loading...