e effect on Dielectrics (Qualitative), Piezo-electricity, pyro-electricity and Ferro-electricity, Applications. Introduction: Dielectrics are insulating materials which do not contain free electrons or the number of such electrons is too low to constitute the electric current. The electrons are tightly bound to the nucleus of the atom in dielectrics. Dielectrics are the materials having electric dipole moment permanently. All dielectrics are electrical insulators and they are mainly used to store electrical energy. Ex: Mica, glass, plastic, water & polar molecules… Electric Dipole: A system of two equal and opposite charges separated by a distance is called electric dipole.