Electric current with respect to ground. Ohm's law states that the current through a conductor between two points is directly proportional to the potential difference across the two points. Introducing the constant of proportionality, the resistance, one arrives at the usual mathematical equation that describes this relationship: where "I" is the current through the conductor in units of amperes, "V" is the potential difference measured "across" the conductor in units of volts, and "R" is the resistance of the conductor in units of ohms. More specifically, Ohm's law states that the "R" in this relation is constant, independent of the current. In
Aluminium-conductor steel-reinforced cable nearby conductors the distribution of current within each conductor will be constrained to smaller regions. The resulting current crowding is termed as the proximity effect. This crowding gives an increase in the effective AC resistance of the circuit, with the effect at 60 Hertz being greater than at 50 Hertz. Geometry, conductivity, and frequency are factors in determining the amount of proximity effect. The proximity effect is result of a changing magnetic field which influences the distribution of an electric current flowing within an electrical conductor due to electromagnetic induction. When an alternating current (AC) flows through an isolated conductor,