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.

EX.PLASTIC ,RUBBER ,AIR,WOOD ,CERAMICS ,PORCELAIN etc.

Insulators are materials that have just the opposite effect on the flow of electrons. They do not let electrons flow very easily from one atom to another.

. Insulators are materials whose atoms have tightly bound electrons. These electrons are not free to roam around and be shared by neighboring atoms.

1. The first electrical systems to make use of insulators were telegraph lines; direct attachment of wires to wooden poles was found to give very poor results, especially during damp weather.

2. the first to produce ceramic insulators were companies in the United Kingdom, with Stiff and Doulton using stoneware from the mid-1840s,

1. Ceramics are extremely strong, showing considerable stiffness under compression and bending.

EX. zirconium dioxide, silicon carbides, silicon nitrides etc.

2. Most ceramics have high melting points,

meaning that even at high temperatures, these materials resist deformation and retain strength under pressure. Silicon carbide and silicon nitride,

3. Some ceramic material conduct electricity at high temperatre EX. Chromium dioxide, porcelain.

4. Ceramics containing iron oxide (Fe2O3) can have magnetic properties similar to those of iron, nickel, and cobalt magnets .

EX.  manganese , barium etc.

ARUN KUMAR