A dielectric capacitor consists of two metal sheets placed on either side of a layer of dielectric material. Dielectrics are materials like glass or plastics (polymers) which are insulators. The behaviour of a dielectric is determined by its dielectric constant value.

Most text books quote the formula shown here to link the value of a capacitor to its plate area (the size of the plate surfaces facing each other), the distance between the plates, and the dielectric constant of the material used. Alas, this simple formula is only approximately correct! Capacitors are designed in a number of different ways.

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