Hi Everyone,

what is the difference between dielectric and insulator?

Can we use Air as a medium between the two plates of the capacitor?

 

Hello,

An insulator can be the dielectric of a capacitor.

What is a Capacitor?
A capacitor is a energy storing device made up of two parallel conductive plates separated by an insulating (dielectric) material. When a voltage is applied across the plates, the electric field in the dielectric displaces electric charges, and thus stores energy. It is assumed that there are no free charges in the dielectric (at least in the ideal case), and that while they are displaced, they are not free to move around as in a conductor. The closest analogy in the mechanical world is probably energy stored by a spring. Dielectrics come in two types, "polar" and "nonpolar". Molecules where the "center-of-gravity" (as it were) of the negative and positive charges are at the same point are nonpolar. If this isn´t the case, the molecule is polar. H 2O, for example, is polar, but H2 is nonpolar.

This is a quote from this page on capacitors:
http://my.execpc.com/~endlr/index.html

Yes, air can be a medium for a capacitor:

figure a is an example of an air capacitor.

This picture comes from this page:
http://www.mikroe.com/old/books/keu/02.htm

All these links come from the EDUCYPEDIA page on capacitors:
http://www.educypedia.be/electronics/capacitors.htm

Bertus

 

The difference isn't very well technically defined that I can tell, an insulator is something that conducts electricity poorly, where according to dictionary.com a dielectric is a material which substances when there is an applied voltage will arrange itself to act as an insulator.

 

I just read about dielectric and insulator on the wiki..

One thing i understood is insulators are materials with low conductivity where as Dielectric is a material with high polerizability.

Thanks guys for your replies.