Introduction

This unit is concerned with the basic elements of electricity: how they relate to each other and how these elements, in turn, relate to more fundamental quantities such as energy.

Electricity is basically the controlled movement of electrons (charge) and the interaction of this charge with the electric and magnetic fields to which they are related and the materials that the charge passes through. This interaction results, primarily, in work being done and energy being dissipated. This ability is what makes electricity wide set of applications. Electricity can generate forces and make things move; electricity can be controlled to encode information - both analogue (that is continuous quantities) and digital (discrete values) - and to manipulate this information in a range of ways that is extremely useful. Examples of the application of electricity are so widespread that it is almost not worthwhile mentioning them. However, without electricity, our society would be completely different - everyday we are surrounded and supported by electricity.