Saturday, September 28, 2013

Physics - Dielectrics

This will be an introduction to dielectrics. Dielectrics are insulators that are mainly used to fill the gaps within capacitors in order to increase the capacitance it can hold. The Dielectric actually weakens the electric field within the capacitor as the electrodes induce a charge on the surfaces of the insulator, but this effect will never completely reverse the electric field.

A Dielectric has a property called electric susceptibility which is designated by Χe. This is a multiplier of the electrical permittivity of free space ε0. This susceptibility is pretty much always an increase meaning its value is greater than one and can range up to 300 times larger depending on what you use as a dielectric. Therefore its effect on a capacitor can be thought of as simply changing the permittivity of free space to the permittivity of the material of the dielectric while keeping the rest of the equations that govern a capacitor the same.

There are other phenomena to be examined but in general they correspond to the insertion or removal of a dielectric, which does not have many applications as they are mainly used to enhance capacitors.

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