Thursday, 15 January 2015

Insulators And Conductors In Electrical Circuits


1) Insulators and conductors in electrical circuits

The electric current can flow in a circuit must therefore not only that the latter is closed but it is formed as a succession of conductive materials.
The presence of an insulator in the loop that forms a circuit has an effect comparable to an open switch.

Some examples of conductors and insulators
Conductor Examples: iron, steel, aluminum, silver, gold, copper, zinc, lead, tin, graphite.
Insulating Examples: glass, air, wood, paper, fabric, plastics

In general all metals (iron, gold, silver, copper, aluminum, zinc etc.) are conductive.
Most other solid materials are insulating (wood, paper, glass, fabrics, plastics etc) with some exceptions such as graphite (as found in pencils).

2) The conductivity test

This test is intended to distinguish conduct rides materials from those insulating.
It relies on the use of an electrical circuit comprising inserting the material to be tested.
Circuit diagram produced for the conductivity test.

Principle of conductivity test:

- If the material is conductive so the current can flow in the circuit and the light can shine.

- If the material is an insulator while the electric current cannot flow and the light does not shine.


Some liquids are conductive but this test is not always sensitive enough to detect the currents that can circulate.