Resistor value

Discussion in 'General Electronics Chat' started by FroceMaster, Oct 22, 2013.

  1. FroceMaster

    Thread Starter Member

    Jan 28, 2012
    400
    4
    Hi,
    Have problems with a debounce switch,
    need a pull up resistor. but dont know the value,
    i know it should go from 5v+ --> resistor --> out to PIC. --> to NO switch --> to ground. and parallel with the switch i have a capasitor 100nf,
    this have Work for long time, but i can remember the value of the resistor
    should it be 10k or 100k or ?
    right now i have A 10K, but it do not Work right,, get many Counts when pressed.

    rgds
    ForceMaster.
     
  2. MrChips

    Moderator

    Oct 2, 2009
    12,432
    3,360
    You have what is commonly referred to as switch bounce.
    It cannot be eliminated with just a capacitor or resistor.
    If this is being interpreted by a microcontroller, you can use software techniques to eliminated the problem.
     
  3. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    #12 likes this.
  4. WBahn

    Moderator

    Mar 31, 2012
    17,720
    4,788
    I've only skimmed the article, but it seems very good. If I ever get the chance to create labs for a circuits course, one of them would be on investigating swtich bounce both in terms of measuring it and in mitigating it.
     
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