# Electric current

The electric field direction within a circuit is by definition the direction that positive test charges are pushed. Thus, these negatively charged electrons move in the direction opposite the electric field. An ampere of current represents the passage of one coulomb of charge per second,… Electric current in a wirewhere the charge carriers are electrons, is a measure of the quantity of charge passing any point of the wire per unit of time.

In alternating current the motion of the electric charges is periodically reversed; in direct current it is not. In many contexts the direction of the current in electric circuits is taken as the direction of positive charge flow, the direction opposite to the actual electron drift.

When so defined the current is called conventional current. Current is usually denoted by the symbol I. The relationship between current and resistance in an electric circuit. Current in gases and liquids generally consists of a flow of positive ions in one direction together with a flow of negative ions in the opposite direction.

To treat the overall effect of the current, its direction is usually taken to be that of the positive charge carrier. A current of negative charge moving in the opposite direction is equivalent to a positive charge of the same magnitude moving in the conventional direction and must be included as a contribution to the total current.

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Current in semiconductors consists of the motion of holes in the conventional direction and electrons in the opposite direction. Currents of many other kinds exist, such as beams of protons, positronsor charged pions and muons in particle accelerators.

Electric current generates an accompanying magnetic fieldas in electromagnets. When an electric current flows in an external magnetic field, it experiences a magnetic forceas in electric motors. The heat loss, or energy dissipated, by electric current in a conductor is proportional to the square of the current.

A common unit of electric current is the amperea flow of one coulomb of charge per secondor 6.

## Electric Current

The centimetre—gram—second units of current is the electrostatic unit of charge esu per second. Commercial power lines make available about amps to a typical home; a watt lightbulb pulls about 0.

For more on electric current, see electricity: Direct electric current and electricity: Learn More in these related Britannica articles:Jul 07,  · An electric current is a flow of electric charge.

In electric circuits this charge is often carried by moving electrons in a wire. It can also be carried by ions in an electrolyte, or by both ions and electrons such as in a plasma..

Electric current is a measure of the flow of charge, as, for example, charge flowing through a wire. The size of the current is measured in amperes and symbolized by i.

An ampere of current represents the passage of one coulomb of charge per second. An electric current is a flow of electric charge.: 2 In electric circuits this charge is often carried by moving electrons in a wire.

## Electric Current

It can also be carried by ions in an electrolyte, or by both ions and electrons such as in an ionised gas. Electric Current. Electric current is the rate of charge flow past a given point in an electric circuit, measured in Coulombs/second which is named Amperes. In most DC electric circuits, it can be assumed that the resistance to current flow is a constant so that the current in the circuit is related to voltage and resistance by Ohm's lausannecongress2018.com standard abbreviations for the units are 1 A = 1C/s.

Electric current. An electric current is usually thought of as a flow of electrons. When two ends of a battery are connected to each other by means of a metal wire, electrons flow out of one end (electrode or pole) of the battery, through the wire, and into the opposite end of the battery.

A simple electric circuit, where current is represented by the letter lausannecongress2018.com relationship between the voltage (V), resistance (R), and current (I) is V=IR; this is known as Ohm's law.

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