Electrical Insulator: Conductor and Non-conductor

A body is said to possess electrification when it attracts other bodies,the attraction being different from the gravitational.The electrification is not a fundamental property of matter because it remain unelectrified under ordinary condition and it becomes electrified only after the electrification has been produced by certain causes.
All substance may broadly be divided into two groups:

  1. Conductors:- copper, aluminium, gold, iron, etc. 
  2. Non-conductors:- Glass, ceramic, plastic, rubber, etc.
  • Conductors:- In case of a conductor,if one point of the body of the substance is by any means electrified, the electrification immediately spreads all to produce easy and smooth flow of electricity.The conductors are metals and alloys.The gold.silver and copper are among the best conductors of electricity and they are followed by aluminium, iron and nickel. Some semi-metals like graphite also fell in this group.The wires made of copper, aluminium, etc, are widely used as the conductors.
              Conductive wire

  •  Non-conductors:- In case of a non-conductor, the electrification produced does not spread over the entire body, but it remain in the neighborhood of  the point where the electrification took place. The non-conductors are also known as the insulators. There is no substance which can be considered as a perfect insulator. But glass , Paraffin, sulphur, plastics, rubber, asbestos and fused quartz are sufficiently good insulator for all practical purpose. The petroleum, oil, etc. are the important liquid insulators. Basically insulator provide the restriction in the flow of current, it does not allow current to pass through it.  The electric insulator may be in the form of solids, liquids or gases. But solid and liquid insulators are important from the commercial point of view. When gas in the normal condition, it conducts electricity to a very small extent. But it can be made to conduct electricity freely, when it has its temperature raised sufficiently and when it has been traversed by rays given out by certain substances such as uranium, radium, thorium, etc.
Non- conductive wood

                     The term dielectric is used to mean a substance capable of supporting an electric stress and its strength or power to resist an electric stress is known as the dielectric strength.

The quality of a good electrical insulator can be summarized as follows:-
  • Desired electrical stability
  • High electrical resistance
  • High dielectric strength
  • High moisture resistance
  • High thermal resistance
  • Low dielectric constant
  • Low power factor
  • Suitable mechanical and physical properties for efficient working, etc.
               
Note:- There are certain substance such as dry wood and paper which have intermediate properties and hence they are sometimes referred to as the semi-conductors. Thus the semiconductors conduct electricity better than insulators but not so well as conductors.
     
         The basic difference between conductor and insulator is that, In conductor current can flow freely but in the case of insulator it does not possible that current can move freely in it. We can simply says that insulator is a substance that have zero conductance, which means it does not allow current to pass through it at any condition. while conductor is opposite to it, Gold has highest conductivity but it can not used it electrical wire because it cost is to high, at the place of gold electrical wire manufacturer industry uses copper and aluminium it also has a good conductivity. Current has a special property it does not follow the high resistance path to flow, It always try to pass through a low resistance or simple path.

No comments