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I Can a capacitor increase voltage beyond initial charge?

  1. Mar 1, 2017 #1
    Question: If you charge a capacitor circuit and then separate the capacitor, does voltage increase beyond the initial source?

    It seams counter intuitive that if you plug a 9 Volt battery into two metal plates and pull the plates apart that you'll get massive voltage spikes, but that's what the equations seem to point to...

    You'll see a diagram of this attached,
    Thanks for your time!

    Attached Files:

  2. jcsd
  3. Mar 1, 2017 #2


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    Why counter-intuitive ? You yourself already write you need to pull (i.e. do work) the plates apart.

    The capacitance decreases, so, in accordance with Q = CV the voltage must increase if the charge remains the same.

    By the way, the guy's name is 'van de Graaff'
  4. Mar 1, 2017 #3
    Ohhhhhhhh I hadn't thought of that work being done... makes sense!

    Can that lead to the voltage being HIGHER than the initial source? Or does it cap off at the voltage of the battery/van de GraAff?

    Thanks again, blown away by that response time by the way!
  5. Mar 1, 2017 #4


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    Yes. Of course, you first have to disconnect the voltage source before starting to pull on the plates.
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