Electrical conductivity or specific conductivity is a measure of a material's ability to conduct an electric current. When an electrical potential difference is placed across a conductor, its movable charges flow, giving rise to an electric current. The conductivity σ is defined as the ratio of the current density to the electric field strength : Electrical conductance is the reciprocal of electrical resistance. ... Conduction is the movement of electrically charged particles through a transmission medium (electrical conductor). ... Electric current is the flow (movement) of electric charge. ... The volt (symbol: V) is the SI derived unit of electric potential difference. ... In electricity, current is the rate of flow of charges, usually through a metal wire or some other electrical conductor. ... In physics, the space surrounding an electric charge or in the presence of a time-varying magnetic field has a property called an electric field. ...

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It is also possible to have materials in which the conductivity is anisotropic, in which case σ is a 3×3 matrix (or more technically a rank-2 tensor) which is generally symmetric. This article is being considered for deletion in accordance with Wikipedias deletion policy. ... In mathematics, a matrix (plural matrices) is a rectangular table of elements (or entries), which may be numbers or, more generally, any abstract quantities that can be added and multiplied. ... In mathematics, a tensor is (in an informal sense) a generalized linear quantity or geometrical entity that can be expressed as a multi-dimensional array relative to a choice of basis; however, as an object in and of itself, a tensor is independent of any chosen frame of reference. ... In linear algebra, a symmetric matrix is a matrix that is its own transpose. ...

Conductivity is the reciprocal (inverse) of electrical resistivity and has the SI units of siemens per metre (S·m^-1) i.e. if the electrical conductance between opposite faces of a 1-metre cube of material is 1 siemens then the material's electrical conductivity is 1 siemens per metre. Electrical conductivity is commonly represented by the Greek letter σ, but κ or γ are also occasionally used. The reciprocal function: y = 1/x. ... In linear algebra, an n-by-n (square) matrix A is called invertible or non-singular if there exists an n-by-n matrix B such that where In denotes the n-by-n identity matrix and the multiplication used is ordinary matrix multiplication. ... // Headline text POOP!! Danny Hornsby (also known as Gnome) is a measure indicating how strongly a Gnome can opposes the flow of electric current. ... The siemens (symbol: S) is the SI derived unit of electric conductance. ... This article is about the unit of length. ... The Greek alphabet (Greek: ) is an alphabet consisting of 24 letters that has been used to write the Greek language since the late 8th or early 9th century BC. It was the first alphabet in the narrow sense, that is, a writing system using a separate symbol for each vowel... Sigma (upper case Σ, lower case σ, alternative ς) is the 18th letter of the Greek alphabet. ... For other uses, see Kappa (disambiguation). ... Gamma (uppercase Γ, lowercase γ) is the third letter of the Greek alphabet. ...

An EC meter is normally used to measure conductivity in a solution. An electrical conductivity meter. ...

Classification of materials by conductivity

• 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 specific frequencies of light, and, most important, with temperature and composition of the semiconductor material.

The degree of doping in solid state semiconductors makes a large difference in conductivity. More doping leads to higher conductivity. The conductivity of a solution of water is highly dependent on its concentration of dissolved salts and sometimes other chemical species which tend to ionize in the solution. Electrical conductivity of water samples is used as an indicator of how salt-free or impurity-free the sample is; the purer the water, the lower the conductivity. In science and engineering, conductors, such as copper or aluminum, are materials with atoms having loosely held valence electrons. ... This article is about metallic materials. ... This article or section is in need of attention from an expert on the subject. ... This article is about the material. ... Look up Vacuum in Wiktionary, the free dictionary. ... A semiconductor is a solid whose electrical conductivity is in between that of a conductor and that of an insulator, and can be controlled over a wide range, either permanently or dynamically. ... This article does not cite any references or sources. ... For other uses, see Temperature (disambiguation). ... Making a saline water solution by dissolving table salt (NaCl) in water This article is about chemical solutions. ... H2O and HOH redirect here. ... For other uses, see Concentration (disambiguation). ... For other meanings of the word salt see table salt or salt (disambiguation). ... Ionization is the physical process of converting an atom or molecule into an ion by changing the difference between the number of protons and electrons. ...

Some electrical conductivities

Drinking water Mineral Water Drinking water is water that is intended to be ingested by humans. ... Deionized water (DI water or de-ionized water; also spelled deionised water, see spelling differences) is water that lacks ions, such as cations from sodium, calcium, iron, copper and anions such as chloride and bromide. ...

Complex conductivity

To analyse the conductivity of materials exposed to alternating electric fields, it is necessary to treat conductivity as a complex number (or as a matrix of complex numbers, in the case of anisotropic materials mentioned above) called the admittivity. This method is used in applications such as electrical impedance tomography, a type of industrial and medical imaging. Admittivity is the sum of a real component called the conductivity and an imaginary component called the susceptivity. [1] In mathematics, a complex number is a number of the form where a and b are real numbers, and i is the imaginary unit, with the property i 2 = −1. ... In electrical engineering, the admittance (Y) is the inverse of the impedance (Z). ... Electrical Impedance Tomography (EIT), is a medical imaging technique in which an image of the conductivity or permittivity of part of the body is inferred from surface electrical measurements. ... Medical imaging designates the ensemble of techniques and processes used to create images of the human body (or parts thereof) for clinical purposes (medical procedures seeking to reveal, diagnose or examine disease) or medical science (including the study of normal anatomy and function). ... In electrical engineering, the susceptance (B) is the imaginary part of the admittance. ...

Temperature dependence

Electrical conductivity is strongly dependent on temperature. In metals, electrical conductivity decreases with increasing temperature, whereas in semiconductors, electrical conductivity increases with increasing temperature. Over a limited temperature range, the electrical conductivity can be approximated as being directly proportional to temperature. In order to compare electrical conductivity measurements at different temperatures, they need to be standardized to a common temperature. This dependence is often expressed as a slope in the conductivity-vs-temperature graph, and can be used: For other uses, see Temperature (disambiguation). ... This article is about metallic materials. ... A semiconductor is a solid whose electrical conductivity is in between that of a conductor and that of an insulator, and can be controlled over a wide range, either permanently or dynamically. ... This article is about proportionality, the mathematical relation. ... For other uses, see Temperature (disambiguation). ... This article is about the mathematical term. ...

where

σ_T′ is the electrical conductivity at a common temperature, T′

σ_T is the electrical conductivity at a measured temperature, T

α is the temperature compensation slope of the material,

T is the measured absolute temperature,

T′ is the common temperature.

The temperature compensation slope for most naturally occurring waters is about 2 %/°C, however it can range between (1 to 3) %/°C. This slope is influenced by the geochemistry, and can be easily determined in a laboratory. Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... The field of geochemistry involves study of the chemical composition of the Earth and other planets, chemical processes and reactions that govern the composition of rocks and soils, and the cycles of matter and energy that transport the Earths chemical components in time and space, and their interaction with... This article does not cite any references or sources. ...

At extremely low temperatures (not far from absolute 0 K), a few materials have been found to exhibit very high electrical conductivity in a phenomenon called superconductivity. A magnet levitating above a high-temperature superconductor, cooled with liquid nitrogen. ...

See also

• Classical and quantum conductivity
• Electrical conduction for a discussion of the physical origin of electrical conductivity.
• Electrical resistance
• Electrical resistivity is the inverse of electric conductivity
• SI electromagnetism units
• Total dissolved solids for a discussion of electrical conductivity of aqueous media
• Transport phenomena

Classical and quantum mechanical views of conductivity have both described the movements of electrons in a metallic solid. ... Conduction is the movement of electrically charged particles through a transmission medium (electrical conductor). ... Electrical resistance is a measure of the degree to which an electrical component opposes the passage of current. ... // Headline text POOP!! Danny Hornsby (also known as Gnome) is a measure indicating how strongly a Gnome can opposes the flow of electric current. ... ... Bottled mineral water usually contains higher TDS levels than tap water Total dissolved solids (often abbreviated TDS) is an expression for the combined content of all inorganic and organic substances contained in a liquid which are present in a molecular, ionized or micro-granular (colloidal sol) suspended form. ... The first edition of Transport Phenomena was published in 1960, two years after having been preliminarily published under the title Notes on Transport Phenomena based on mimeographed notes prepared for a chemical engineering course taught at the University of Wisconsin during the academic year 1957-1958. ...

External links

• Measurement of the Electrical Conductivity of Glass Melts Measurement Techniques, Definitions, Electrical conductivity Calculation from the Glass Composition
• Periodic Table of Elements Sorted by Electrical Conductivity