Ampere the watt, the ohm and the volt. Rather than a definition in terms of the force between two current-carrying wires, it has been proposed that the ampere should be defined in terms of the rate of flow of elementary charges. Since a coulomb is approximately equal to elementary charges (such as those carried by protons, or the negative of those carried by electrons), one ampere is approximately equivalent to elementary charges moving past a boundary in one second. ( is the reciprocal of the value of the elementary charge in coulombs.) The proposed change would define 1 A as being
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,