Joseph, 1797, 1878, US-amerik. Physiker; arbeitete bes. über Induktion, deren Einheit nach ihm benannt wurde.
(1797-1878) US physicist, inventor of the electromagnetic motor 1829 and of a telegraphic apparatus. He also discovered the principle of electromagnetic induction, roughly at the same time as Michael Faraday, and the phenomenon of self-induction. The unit of inductance, the henry, is named for him.
Born in Albany, New York, Henry studied at Albany Academy, where he became professor 1826, moving 1832 to New Jersey College (later Princeton). He was the Smithsonian Institution's first director, from 1846.
By 1830, he had made powerful electromagnets by using many turns of fine insulated wire wound on iron cores. In that year he anticipated Faraday's discovery of electromagnetic induction (although Faraday published first). In 1835 he developed the relay (later to be much used in electric telegraphy).
In astronomy, Henry studied sunspots and solar radiation, and his meteorological studies at the Smithsonian led to the founding of the US Weather Bureau.
O. Henry, eigtl. William Sydney Porter, 1862, 1910, US-amerik. Schriftst. (Kurzgeschichten).
Pen name of William Sydney Porter (1862-1910)
US short-story writer. His collections include Cabbages and Kings 1904 and The Four Million 1906. His stories are written in a colloquial style and employ skilled construction with surprise endings.
Nach dem amerikan. Physiker J. Henry (1797, +1878) benannte Maßeinheit für Selbstinduktion (1 Voltsekunde/Ampere); Zeichen: H.
ETYM From Joseph Henry, an American physicist.
A unit of inductance in which an induced electromotive force of one volt is produced when the current is varied at the rate of one ampere per second; SYN. h.
The unit of inductance in which an induced electromotive force of one volt is produced when the current is varied at the rate of one ampere per second.
Unit of electrical inductance.
Unit of electrical inductance: inductance of circuit in which one volt is induced by current varying at one ampere per second.
Si unit (symbol h) of inductance (the reaction of an electric current against the magnetic field that surrounds it). One henry is the inductance of a circuit that produces an opposing voltage of one volt when the current changes at one ampere per second.
It is named for the us physicist Joseph Henry.
The unit of inductance. A current changing at a rate of one ampere per second will generate one volt across an inductance of one henry. In practice, a henry is a very large unit; inductances measured in millihenries (mH = 10–3 h), microhenries H = 10–6 h), or nanohenries (nH = 10–9 h) are more commonly encountered. Abbreviated h. See also inductance.