capacitance calculation

Discussion in 'General Electronics Chat' started by samjesse, Aug 14, 2009.

  1. samjesse

    Thread Starter Active Member

    Sep 14, 2008
    202
    0
    the formula to calculate the capacitance is

    C = (ε A)/d

    where ε is dielectric absolute permittivity
    A is the overlap area in what units?
    d is the distance between the plates in meters

    what is the formula to use the relative permittivity instead?

    Thank you
     
  2. studiot

    AAC Fanatic!

    Nov 9, 2007
    5,005
    513
    area is measured in square metres in the MKS (ISO) system.
     
  3. rspuzio

    Active Member

    Jan 19, 2009
    77
    0
    > A is the overlap area in what units?
    > d is the distance between the plates in meters

    Since you will measure d in meters, to be consistent, you
    need to measure A in square meters.

    > what is the formula to use the relative permittivity instead?

    Write \epsilon = \epsilon_{rel} \epsilon_0, where
    \epsilon_{rel} is the relative permittivity (a.k.a.
    dielectric constant) and \epsilon_0 is the vacuum
    permittivity (which equals 8.85 \times 10^{-12} \, F/m).
     
    Last edited: Aug 14, 2009
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