Electrotechnics: Basics


What is electrical current?

Electric current - a flow of electric charge.

In electrical circuits, current is created mostly by moving the free charges in the conductor. Electric current can also exist in fluids where the free charge carriers are ions. These fluids are electrolytes and molten substances. The current in the plasma is carried out both ions and electrons. Besides possible current transfer, e.g., in vacuo, and the current in the semiconductors.

The SI unit of electric current the ampere (A). Denoted by the Latin letter I. This value characterizes the rate of change of the charge in the section of the measured flow. One ampere of current - this is such a value at which the one second time the flow passes through a section of the quantity of electricity to one Coulomb (C).

Determination of electrical current

A device which measures the amount of electric current, called - ammeter.

Electric current is accompanied by a primarily magnetic phenomena, as well as heat conductors.

According on how the electrical current varies with time, are direct (DC) current that does not vary in magnitude and direction over time, and a variable current that varies with time in size and/or direction. In turn, depending on how the changes over time are distinguished alternating current (AC) (frequency sinusoidal currents, and the like) and the pulse (no periodicity interlace).

Chemical current sources - a source of direct (DC), and industrial electric network, which is also used in households - is a periodic alternating current (AC) of a single frequency sinusoidal current (oscillation).

Date: 01.31.2016

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© Valentin Grigoryev


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