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Homework Help: Capacitance of parallet plate with dielectric spheres in between

  1. Jun 3, 2008 #1
    I want to calculate the capacitance of a system consisting a parallel plate and dielectric spheres of different radius and dielectric strength in between the plates.
    please give some mathematical derivation.
    I really need to know it,my career depends on it.
    Please help me.
    thanks & regards
  2. jcsd
  3. Jun 3, 2008 #2
    capacitance in parallel is same as resistor in series and vice versa.
    c = permittivity*dielectric*area/distance

    If you have a sphere, it will be an integration of series of capacitance depending on the diameter of the sphere at different location. At the tip of the sphere, the dielectric distance/space is less compared to the middle of the sphere. For example if you had a circle, the diameter maybe say 1m, but it is not 1m x 1m. Instead it is 1m diameter but as you cut and move along the circle, it becomes 0.99m,0.98m,0.979999m etc.

    For start, i suggest using a square dielectric. Take 3 squares, with 2 of them being the same length but 1/2 the length of the first one. Put the 2 smaller square in series (next to each other). Stack the bigger square on top of them. The circuit will look just like 2 resistor in series parallel with the other.
  4. Jun 3, 2008 #3


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    Staff Emeritus
    Science Advisor
    Homework Helper

    This might be a situation where doing a measurement is much easier than doing the calculation.
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