22 Facts About Electrical current

An electric current is a stream of charged particles, such as electrons or ions, moving through an electrical conductor or space.

SI unit of electric Electrical current is the ampere, or amp, which is the flow of electric charge across a surface at the rate of one coulomb per second.

Conventional symbol for Electrical current is, which originates from the French phrase intensite du courant, .

Flow of positive charges gives the same electric Electrical current, and has the same effect in a circuit, as an equal flow of negative charges in the opposite direction.

Since Electrical current can be the flow of either positive or negative charges, or both, a convention is needed for the direction of Electrical current that is independent of the type of charge carriers.

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The direction of conventional Electrical current is arbitrarily defined as the direction in which positive charges flow.

In contrast, direct Electrical current refers to a system in which the movement of electric charge in only one direction .

Direct Electrical current is produced by sources such as batteries, thermocouples, solar cells, and commutator-type electric machines of the dynamo type.

Alternating Electrical current can be converted to direct Electrical current through use of a rectifier.

Natural observable examples of electric Electrical current include lightning, static electric discharge, and the solar wind, the source of the polar auroras.

Man-made occurrences of electric current include the flow of conduction electrons in metal wires such as the overhead power lines that deliver electrical energy across long distances and the smaller wires within electrical and electronic equipment.

In electronics, other forms of electric Electrical current include the flow of electrons through resistors or through the vacuum in a vacuum tube, the flow of ions inside a battery, and the flow of holes within metals and semiconductors.

Biological example of Electrical current is the flow of ions in neurons and nerves, responsible for both thought and sensory perception.

Electric current can be directly measured with a galvanometer, but this method involves breaking the electrical circuit, which is sometimes inconvenient.

So, in metals where the charge carriers are negative, conventional Electrical current is in the opposite direction to the overall electron movement.

In other conductive materials, the electric Electrical current is due to the flow of both positively and negatively charged particles at the same time.

The Electrical current-carrying electrons in the conduction band are known as free electrons, though they are often simply called electrons if that is clear in context.

Conventionally, if the moving charges are positive, then the Electrical current density has the same sign as the velocity of the charges.

For negative charges, the sign of the Electrical current density is opposite to the velocity of the charges.

In SI units, Electrical current density is expressed in the SI base units of amperes per square metre.

Where is the Electrical current, measured in amperes; is the potential difference, measured in volts; and is the resistance, measured in ohms.

Any accelerating electric charge, and therefore any changing electric Electrical current, gives rise to an electromagnetic wave that propagates at very high speed outside the surface of the conductor.