Electrical principles - Properties

Conductors

The outermost orbit path for electrons is known as the valence shell, or conduction band. An atom with only a small number of electrons in the valence shell allows the electrons to move freely. Materials that are made up of atoms with these 'free electrons' are known as conductors.

Most metals are good conductors. Examples of good conductors include gold, silver and copper because each of these metals has only one electron in its valence shell.

 

A copper conductor

The application of some kind of force, eg a magnetic field or voltage, will cause electrons in a conductor to freely interchange between atoms.

Conductance is defined as the ability to conduct current, which is the opposite of resistance. If a wire has a high conductance, it will have a low resistance. There is no perfect conductor. All conducting materials offer some resistance to electron flow.