Electrical conductivity
Electrical conductivity is a measure of how well a material accommodates the transport of electric charge. Conductance is an electrical phenomenon where a material contains movable particles with electric charge, which can carry electricity. When a difference of electrical potential is placed across a conductor, its movable charges flow, and an electric current appears.A conductor such as a metal has high conductivity, and an insulator like glass or a vacuum has low conductivity. A semiconductor has a conductivity that varies widely under different conditions, such as exposure of the material to electric fields or certain frequencies of light.
Electrical conductivity is the reciprocal of electrical resistivity (1/[Ω·m]). Its SI derived unit is the siemens per metre, (A²s³m-3kg-1) (named after Werner von Siemens). It is the ratio of the current density to the electric field strength. This applies also to the electrolytic conductivity of a fluid.
For a discussion of the physical origin of electrical conductivity, see electrical conduction.