dielectric (rus. диэлектрик) — term coined by Michael Faraday and used to refer to media that cannot conduct electric current.


Dielectrics are characterised by their extremely low direct-current conductivity. Free charges present in any conductor are moved by the electrostatic field and after a period of time, called Maxwell relaxation time, create an opposite field, which completely compensates the external field. Maxwell relaxation time is inversely proportional to the conductivity of the material, so in the absence of electrical conductivity associated with the presence of free charge carriers, the time needed for creation of the compensating field tends to infinity. As a result, the external electrostatic field in the dielectric is not fully compensated. It causes polarisation of the atoms, molecules or ions, whose electric fields in their entirety form the inverse polarisation field. Such an inverse field is always smaller than the external field.


  • Khokhlov Dmitry R.


  1. Physical Encyclopedic Dictionary (in Russian). — Moscow: Bol'shaja Rossijjskaja ehnciklopedija, 1995. — 928 pp.

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