What is an Insulator?
In an Insulators, electrons are not free to roam around and be shared by neighboring atoms. They are tightly bound electrons. Some common Insulator materials are glass, plastic, rubber, air, Teflon and wood. Vacuum is also an insulator, though it is not actually a material.
Definition of an Insulator?
Insulators are simply material that does not conduct electrical current. Most electrical conductors are covered by insulation materials. Insulators possess a high resistivity and low conductivity. Their atoms have tightly bound electrons that do not move throughout the material. Because the electrons are static and not freely roaming, a current cannot easily pass. In addition to protecting loss of current, insulators make an electrical current more efficient by concentrating the flow.
The property that distinguishes an insulator is its resistivity. Insulators have higher resistivity than semiconductors or conductors. The most common examples are non-metals. A perfect insulator does not exist because even insulators contain small numbers of mobile charges (charge carriers) which can carry current.
In addition, all insulators become electrically conductive when a sufficiently large voltage is applied that the electric field tears electrons away from the atoms. This is known as the breakdown voltage of an insulator. A much larger class of materials, even though they may have lower bulk resistivity, are still good enough to prevent significant current from flowing at normally used voltages, and thus are employed as insulation for electrical wiring and cables. Examples include rubber-like polymers and most plastics which can be thermoset or thermoplastic in nature.
An insulating material used in bulk to wrap electrical cables or other equipment is called Insulation. The term insulator is also used more specifically to refer to insulating supports used to attach electric power distribution or transmission lines to utility poles and transmission towers. They support the weight of the suspended wires without allowing the current to flow through the tower to ground.