Parallel Plate Capacitor

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The capacitance of flat, parallel metallic plates of area A and separation d is given by the expression above where:

= permittivity of space and

The Farad, F, is the SI unit for capacitance, and from the definition of capacitance is seen to be equal to a Coulomb/Volt.

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Capacitance = k x

x area / separation

For parallel plates of area A = m² and separation d = m,
with relative permittivity k= , the capacitance is

=

= x10^ F = pF

Capacitance of Parallel Plates

The electric field between two large parallel plates is given by Show

The voltage difference between the two plates can be expressed in terms of the work done on a positive test charge q when it moves from the positive to the negative plate.

It then follows from the definition of capacitance that