Technical Glossary Dielectric constant

[Dielectric constant]

The dielectric constant is the ease of polarization (indicating the size of the quantity of electricity stored) and is a standard used to evaluate its performance as an insulator.

Using an example of a condenser, an insulator is placed between pole plates and voltage is applied, electricity will not flow, though a phenomenon called polarization where positive and negative charges in molecules separate will occur, so electricity will be stored. At this point, the quantity of electricity stored is proportional to the intensity of the magnetic field and area of the pole plates, so it will increase; the rate of change in this event is called the dielectric constant. If the dielectric constant increases, the quantity of electricity stored will increase.
Generally, specific inductive capacity (ratio of the dielectric constant of an insulator and the dielectric constant of a vacuum) is used rather than the dielectric constant. Having a small specific inductive capacity is preferred for an insulator.
In addition, this value is dependent on the frequency and temperature, so care must be taken upon usage.