Classification of Dielectric Materials

The dielectric materials may be classified as solid, liquid and gas dielectrics.

Solid form	In solid form they may be polymeric such as nylon, pvc, rubber, backlite, asbestos and wool or may belong to the ceramic family such as glass, silica, mica, porcelain, etc.
Liquid form form	In liquid form they may be mineral insulating oils, synthetic insulating oils, etc.
Gaseous form	In gaseous form they may be air, nitrogen, sulphur hexafluoride, inert gases etc.

The dielectrics can also be classified as active and passive dielectrics based on their applications.

S.No	Active Dielectrics	Passive Dielectrics
1.	When dielectric is subjected to external electric field, if the dielectric actively accept the electricity, then they are termed as active dielectrics.	These dielectrics are also called insulating materials. As the name itself suggest that it will act as an insulator, conducting will not take place through this dielectrics.
2.	Thus active dielectrics are the dielectrics which can easily adapt itself to store the electrical energy in it.	Thus passive dielectrics are the dielectrics which restricts the flow of current in it.
3.	Examples: Piezo-electric materials, Ferro-electric materials etc.,	Example: All insulating materials such as glass, mica, etc.,