Dielectric materials maintain an electric field with a minimum loss of power, and are poor conductors of electric current. They have no loosely bound, or free, electrons that may drift through the material. Instead, electric polarization occurs.
A common measure of the dielectric properties of a material is the dielectric constant. The dielectric constant can be defined as the tendency of a material to resist the flow of an electric current across the material. The lower the value of the dielectric constant, the greater its resistance to the flow of an electrical current.