Question about pushbutton and limit switch...

Discussion in 'General Electronics Chat' started by Gibling, Jul 3, 2009.

  1. Gibling

    Thread Starter Member

    May 28, 2009
    Say I push down an On-On SPDT push button: when I hear the first click, is that when the contacts transfer, or do they transfer after the second click when the button resets back to it's original position? Also, On-On means each time you push the button, the contacts transfer and stay transfered until the next push, right?

    Say I have a spring return push rod limit switch: when the rod resets, does it reset the contacts as well? In other words, is it momentary, like some push buttons? I want something that gets pushed, changes contacts, resets while maintaining these new contacts, gets pushed again, returns to the original contacts, resets and repeats. Any recommendations?

  2. beenthere

    Retired Moderator

    Apr 20, 2004
    If you have a meter to check continuity, it is easy to see what is happening. Another way out is to go to the manufacturer's web site and look up the switch to see the explicit description of the function.

    If your PB switch is retained function, then one push closes and the next opens.
    The key is to look for "momentary" in the switch description. If it does not say that, then it is likely to be definite-acting.

    Limit switches tend to be momentary in construction - otherwise they say the traveller is at the end of travel when it is not.
  3. Gibling

    Thread Starter Member

    May 28, 2009
    I don't have a push button yet so I can't test it out. The thing is I need the contacts to transfer on the first click, before the spring pushes it back out, or my setup wont work. Is this generally how it works?

    I've been looking around on some sites but none really say specifically what occurs...