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Non-parallel plate capacitance

  1. Oct 31, 2007 #1
    Im having trouble calculating the capacitance of a non-parallel plate capacitor where seperation at one edge is d-a and the other it is d+a, assuming a<<d. I'm supposed to prove that C= epsilon_not A/d (1+a^2/3d^2). Thanks for the help.
  2. jcsd
  3. Nov 1, 2007 #2


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    Science Advisor

    The equations for the distance between the plates is x=d+ay/L.
    The surface charge ~V/x.
    Integrate V/(d+ay/L) from y=-L/2 to +L/2.
    Expand the logarithm.
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