What is the definition of the term dielectric?

Answer 1

'Dielectric' is often used in a general sense to refer to a material (such as ceramic, mica, plastic or paper) which is a poor conductor of electricity.

This term is used in the classical description of a capacitor -- two electric conductors separated by a dielectric. By applying electric charge to one conductor an electric field is created. The dielectric allows the electric field to pass through it and affect the other conductors; however the dielectric prevents electrons from flowing between the conductors, so the electric field remains (and the charge remains stored on the conductor).

[Side note for beginners: An electric field creates a force (measured in Volts) upon an electron or charged particle which tends to make it move. The conductor allows electrons to move easily within it. The dielectric resists the movement of electrons in it.]

More generally, we speak of a 'Dielectric Field' as a mathematic description of how electric charge influences the properties of the space around it. The Dielectric field interacts with space and with any material in the space to create an 'Electric Field'.

In simple terms, the electric field at any point is the product of the dielectric field at that point and the 'Dielectric Constant' of the material at that point. In more general terms, the 'electric field vector' at a point is the tensor product of the 'dielectric field vector' and the 'dielectric tensor' of the material at that point.

The dielectric field is not a measurable entity, but rather a mathematical tool that allows us accurately to model the electric field, which is measurable.

The article on Dielectrics at http://en.wikipedia.org/wiki/Dielectric provides more description, especially on the dielectric field model.