Generator (Encyclopedia of Science)
A generator is a machine that converts mechanical energy into electrical energy. Generators can be subdivided into two major categories depending on whether the electric current produced is alternating current (AC) or direct current (DC). The basic principle on which both types of generators work is the same, although the details of construction of the two may differ somewhat.
Principle of operation
In 1820, Danish physicist Hans Christian Oersted (1777851) discovered that an electric current created a magnetic field around it. French physicist André Marie Amperè (1775836) then found that a coil of wire with current running through it behaved just like a magnet.
In about 1831, English physicist Michael Faraday (1791867) discovered the scientific principle on which generators operate: electromagnetic induction. By reversing the work of Oersted and extending the work of Amperè, Faraday reasoned that if a current running through a coiled wire could produce a magnetic field, then a magnetic field could induce (generate) a current of electricity in a coil of wire. By moving a magnet back and forth in or near a coil of wire, he created an electrical current without any other source of voltage feeding the wire.
(The entire section is 935 words.)
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