Electrical conductivity

Electrical conductivity is a measure of how well a material accommodates the transport of electric charge. Its SI derived unit is the siemens per metre, (A2s3m-3kg-1) (named after Werner von Siemens).

Classification of materials by conductivity

Scientists often divide materials into three classes based upon their respective conductivities:

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• A conductor such as a metal has high conductivity.
• An insulator like glass or a vacuum has low conductivity.
• The conductivity of a semiconductor is generally intermediate, but varies widely under different conditions, such as exposure of the material to electric fields or certain frequencies of light.