I just want to know the similarities and dissimilarities between them.

  • 3
    $\begingroup$ A dielectric material is an insulator that can be polarized by an electric field. A simple search would have solved your problem. $\endgroup$
    – Mr. Xcoder
    Commented Aug 20, 2017 at 13:29
  • 4
    $\begingroup$ I'm voting to close this question as off-topic because of insufficient prior effort. $\endgroup$
    – garyp
    Commented Aug 20, 2017 at 15:01

1 Answer 1


An electrical insulator is a material whose internal electric charges do not flow freely, and therefore make it very hard to conduct an electric current under the influence of an electric field.

Most insulators have a large band gap. This occurs because the "valence" band containing the highest energy electrons is full, and a large energy gap separates this band from the next band above it. There is always some voltage (called the breakdown voltage) that gives electrons enough energy to be excited into this band. Once this voltage is exceeded the material ceases being an insulator, and charge begins to pass through it.

A dielectric on the other hand is an electrical insulator that can be polarized by an applied electric field. When a dielectric is placed in an electric field, electric charges do not flow through the material as they do in a conductor, but only slightly shift from their average equilibrium positions causing dielectric polarization. Because of dielectric polarization, positive charges are displaced toward the field and negative charges shift in the opposite direction. This creates an internal electric field that reduces the overall field within the dielectric itself.

Overall: While the term insulator implies low electrical conduction, dielectric typically means materials with a high polarizability.

Source - Sameer Saxena


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