ABSTRACT
This chapter has been included in order to provide a brief overview of electric current and Ohm's law for those who may not have had the benefit of any previous study of electrical principles. It begins with an explanation of electric current as the organised movement of electric charge and shows how the resistance of a conductor depends on the physical dimensions of the conductor and the material of which it is made. Firstly, because electric current requires a conductive path in order to flow, there is no leakage or fringing path in an electric circuit that would be equivalent to the escape of flux from a magnetic circuit. The chapter explains how electric current is the organised movement of electrons in metallic conductors from a point of greater electric potential to one with a lesser electric potential. Because of the losses associated with it, internal resistance is important in many electrical applications.
