Electricity

:Separate-but related articles are Electrical energy, and Electric power

Electric current

The electric charge which occurs naturally within conductors can be forced to flow, while the charges within insulators are locked in place and cannot be moved. Devices that use charge flow principles in materials are called electronic devices. A flow of electric charge is called an electric current.

Related Topics:
Conductor - Insulator - Electronic devices - Electric current

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A direct current (DC) is a unidirectional flow; alternating current (AC) is a flow whose time average is zero, but whose energy capability (RMS level) is not zero. With AC the electric current repeatedly changes direction.

Related Topics:
Direct current - Alternating current - RMS - Direction

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See electrical conduction

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Ohm's Law is an important relationship describing the behaviour of electric currents:

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:V = I cdot R ,

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where

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V is the applied voltage, measured in volts

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I is the current, measured in amperes

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R is the resistance, measured in ohms

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For historical reasons, electric current is said to flow from the most positive part of a circuit to the most negative part. The electric current thus defined is called conventional current. It is now known that, depending on the type of conductor, an electric current can consist of a flow of charged particles in either direction, or even in both directions at once. The positive-to-negative convention is widely used to simplify this situation. If another definition is used - for example, "electron current" - it should be explicitly stated.

Related Topics:
Current - Conventional current

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