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ESD Protection

  1. Sep 29, 2008 #1

    I have a switch connected to a motherboard.
    During ESD test with 8000kV (directly on the switch) the ESD spike caused my system to reboot, and I need some kind of surge protection betwee nthe switch and motherboard.

    I am not sure what I need to look for?
    Can anyone suggest a component I can use? I need to put spikes to ground but I´m not sure about other specifications.

  2. jcsd
  3. Sep 29, 2008 #2


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    I'd probably use a relay, or opto-coupler, or galvanic isolator. Actually, if you really are using 8 MV (!) you should be using a contactor or vacuum switch, something that's meant to handle that sort of voltage without arcing (assuming you have any current behind your voltage). You're lucky your system just reboots, and that you haven't burnt anything out (yet).
  4. Sep 29, 2008 #3


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    Pretty sure that's a typo, and temunjin meant 8kV. 8kV "contact" discharge is a pretty standard reliability/immunity test, as is 15kV "air" discharge.

    temunjin, there are a number of standard techniques for designing for EMC compliance, which includes ESD immunity. The subject is too big to address very well in just this thread, so here are some suggested initial sources of information that you should read. Once you've done some background reading, please feel free to post follow-up questions here.

    [1] "Protection of Electronic Circuits from Overvoltages", by Standler.

    [2] "ESD Immunity in System Designs, System Field Experiences and Effects of PWB Layout", by Smith and Nakauchi:


  5. Sep 29, 2008 #4

    Ivan Seeking

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    Perfect timing! Thanks berkeman.
  6. Oct 14, 2008 #5
    Thanks for the tips and links.

    ...and yes, I meant 8kV (not 8000kv).

    The pdf you (berkman) linked was interesting, but due to tight time frames right now I have changed the switch for one with a higher rating. Hopefully it will work.

  7. Oct 14, 2008 #6
    a simple Metal Oxide Varistor, maybe?
  8. Oct 15, 2008 #7
    was my first thought as well, but it had no effect...

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