Electrical Insulators

Electrical insulators

Electrical insulators are different from electrical conductors. Electrical conductors are those materials which propagate the ease of flow of electricity throughout them. They allow charges to flow easily through them. Insulators, on the other hand, are materials that do not allow electric charges to flow freely through them.

Conductors have a property called conductivity which defines their ability to conduct electricity. For insulators, their effectiveness is determined based on how much resistance they offer to the flow of electricity. This property, in contrast to conductivity, is called resistivity.

Examples for Insulators are given below

  • Plastic
  • Rubber
  • Wax
  • Wood
  • Glass
  • Air
  • Styrofoam

Most nonmetals are poor conductors and therefore good insulators. They do not have free electrons available to conduct electricity. Materials with larger resistivity values, offer greater resistance to the flow of electric current and are therefore better insulators. For example, glass has a resistivity value of 1012 Ωm (ohm metre), and copper has a value of resistivity of 10-12 Ωm.

General properties that affect the effectiveness of an insulator are

  • High resistivity as we have already discussed
  • Breakdown voltage
  • Atomic structure
  • Air permeability

Insulators are mainly used in applications where the prevention of flow of electric charges is required. These materials work as effective nonconductors since they lack movable electric charges required to propagate electric current. Electrical insulators are used mainly as parts in electrical equipment. For example, the electrical wires which transfer electricity through households, are covered with insulation material to prevent any safety hazards. The electrical plugs have an insulated covering to prevent electricity flowing from the metal socket (conductor) to your body (also a conductor) by stopping the flow of electrons.

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Practise This Question

The glass is an example of: