Electrical conductivity

From Biocrawler, the free encyclopedia.

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 κ (kappa), but also σ (sigma) or γ (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 edit  (http://www.biocrawler.com/w/index.php?title=Template:SI_electromagnetism_units&action=edit)
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
watt	W	V·A = kg·m2·s−3	Electrical power
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	Wb/A = V·s/A = kg·m2·s−2·A−2	Inductance
henry per metre	H/m	kg·m·s−2·A−2	Permeability
(dimensionless)	χ	-	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)ca:Conductivitat elèctrica

cs:Elektrická vodivost da:Elektrisk ledningsevnees:Conductancia eléctrica fi:Sähkönjohtavuus fr:Conductivité électrique nl:Elektrische geleidbaarheid pl:Konduktywność pt:Condutividade elétrica ro:Conductibilitate electrică sl:električna prevodnost sv:Konduktivitet

Wikipedia (http://en.wikipedia.org/wiki/Main_Page) Conductivity (http://en.wikipedia.org/wiki/Conductivity) version history (http://en.wikipedia.org/w/index.php?title=Conductivity&action=history) GNU Free Documentation Lizenz (http://en.wikipedia.org/wiki/Wikipedia:Text_of_the_GNU_Free_Documentation_License) CC-by-sa (http://creativecommons.org/licenses/by-sa/2.5/)

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