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.

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]).

SI electricity units

SI electromagnetism units edit  (http://www.wordiq.com/definition/Template: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:

• "The Theoprax Method" (http://www.theoprax-research.com/theoprax.pdf) (PDF)
• Cordis Online Abstract (http://www.theoprax-research.com/cordisth.htm)

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