Electrical conductivity

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Electrical conductivity is the measure of a material's ability to allow the transport of an electric charge. Its SI is the siemens per metre, (A2s3m−3kg−1) (named after Werner von Siemens) or, more simply, Sm−1.

It is the ratio of the current density to the electric field strength. It is equivalent to the electrical conductance measured between opposite faces of a 1-metre cube of the material under test.

  • The symbol for electrical conductivity is (kappa), and also (sigma) or (gamma).

Electrical conductance is an electrical phenomenon where a material contains movable particles with electric charge (such as electrons), which can carry electricity. When a difference of electrical potential is placed across a conductor, its electrons 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.

Electrical conductivity is the reciprocal (or inverse) of electrical resistivity.