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). It is the ratio of the current density to the electric field strength. This applies also to the electrolytic conductivity of a fluid.
- As symbol for electrical conductivity we find <math>\kappa<math> (kappa), but also <math>\sigma<math> (sigma) or <math>\gamma<math> (gamma).
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.
SI electricity units
| SI electromagnetism units | |||
|---|---|---|---|
| Name | Symbol | Dimensions | Quantity |
| ampere (SI base unit) | A | A | Current |
| coulomb | C | A·s | Electric charge, Quantity of electricity |
| volt | V | J/C = kg·m2·s−3·A−1 | Potential difference |
| ohm | Ω | V/A = kg·m2·s−3·A−2 | Resistance, Impedance, Reactance |
| ohm metre | Ω·m | kg·m3·s−3·A−2 | Resistivity |
| farad | F | C/V = kg−1·m−2·A2·s4 | Capacitance |
| farad per metre | F/m | kg−1·m−3·A2·s4 | Permittivity |
| reciprocal farad | F−1 | kg1·m2·A−2·s−4 | Elastance |
| siemens | S | Ω−1 = kg−1·m−2·s3·A2 | Conductance, Admittance, Susceptance |
| siemens per metre | S/m | kg−1·m−3·s3·A2 | Conductivity |
| weber | Wb | V·s = kg·m2·s−2·A−1 | Magnetic flux |
| tesla | T | Wb/m2 = kg·s−2·A−1 | Magnetic flux density |
| ampere per metre | A/m | m−1·A | magnetic induction |
| ampere-turns per weber | A/Wb | kg−1·m−2·s2·A2 | Reluctance |
| henry | H | V·s/A = kg·m2·s−2·A−2 | Inductance |
| henry per metre | H/m | kg·m·s−2·A−2 | Permeability |
| (dimensionless) | - | - | Magnetic susceptibility |
See also
- electrical conduction for a discussion of the physical origin of electrical conductivity
- electrical resistance
- electrical resistivity
External links
For the use of conductivity measurements to record pH spectra which shows the interaction between different molecules as a function of the degree of dissociation of their functional groups, see the following external links:
Categories: Electrochemistry | Electromagnetism | Physical quantity