## ::Voltage

### ::concepts

Voltage::electric    Between::points    Field::current    Charge::voltages    Energy::pressure    Battery::circuit

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Voltage, electric potential difference, electric pressure or electric tension (denoted V or U) is the difference in electric potential energy between two points per unit electric charge. The voltage between two points is equal to the work done per unit of charge against a static electric field to move the charge between two points and is measured in units of volts (a joule per coulomb).

Voltage can be caused by static electric fields, by electric current through a magnetic field, by time-varying magnetic fields, or some combination of these three.<ref>Demetrius T. Paris and F. Kenneth Hurd, Basic Electromagnetic Theory, McGraw-Hill, New York 1969, ISBN 0-07-048470-8, pp. 512, 546</ref><ref>P. Hammond, Electromagnetism for Engineers, p. 135, Pergamon Press 1969 OCLC 854336.</ref> A voltmeter can be used to measure the voltage (or potential difference) between two points in a system; often a common reference potential such as the ground of the system is used as one of the points. A voltage may represent either a source of energy (electromotive force), or lost, used, or stored energy (potential drop).

Voltage sections
Intro  Definition  Volt  Hydraulic analogy   Applications   Measuring instruments  Typical voltages  Galvani potential vs. electrochemical potential  See also  References  External links

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