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Buzzer timing

Discussion in 'General Electronics Discussion' started by william light, Oct 25, 2012.

  1. william light

    william light

    1
    0
    Oct 25, 2012
    Hi all new here but looking for a bit of help. I have a simple circuit which sounds a buzzer as a series of magnets pass the reed switch. Problem is when the magnets pass quickly the buzzer sounds constantly where as i want it to pip for every single magnet pass. Tried different reed switches with no joy, can i add a capacitor or something inline to the buzzer?
    Many thanks all
     
  2. CocaCola

    CocaCola

    3,635
    4
    Apr 7, 2012
    There is going to be a physical 'latch' and 'unlatch' time to the reed switch, if the speed of the magnet passing is faster than the latch time it won't latch or if the speed of multiple magnets passing exceeds the unlatch time it will be a constant...
     
  3. davenn

    davenn Moderator

    13,246
    1,745
    Sep 5, 2009
    hi william,
    welcome to the Electronics Point forums :)

    You could try a Hall effect sensor instead, they have much faster switching times than reed relays

    cheers
    Dave
     
  4. duke37

    duke37

    5,211
    718
    Jan 9, 2011
    Reed switches a quite fast. I have used a reed switch to measure the speed of a shaft up to 1000rpm. In this case, the switch spent most of the time unenergised.

    Perhaps the magnets are too close together. You could try alternating the magnet polarity so that the field goes through zero.
     
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