Electrical properties of materials
© copyright M.J.Morris 2002
At the beginning of this section it was stated that electricity is concerned with the movement of charged particles. There are three charge carriers that can move in electrical circuits.
Note it does not make sense to include protons in this list because protons are locked into the atoms. Therefore the only time a proton moves in an electrical circuit is when the whole atom moves. The atom will only move it has become ionised (otherwise it is acts like a neutral particle and is not affected by electric fields). The movement of ions has been included in the above list
As ions are atoms, ions can only move in materials in which the atoms are free to move ie liquids and gases. Electrons can move in some liquids and gases and can also move in some solid materials. In the majority of electrical circuits electricity flows through solid materials (wires etc). Therefore unless otherwise stated the charge carriers referred to in this text will be electrons. Electrons do not readily move through all types of materials, in order for them to move they must be free of their parent atoms. In the next sections we will look at how the atomic structure of the material affects the number of free electrons available.