oerstedn.
/ˈəːstᵻd/, /ˈəːstɛd/, U.S. /ˈərˌstɛd/ Physics.† 1. (In form oerstedt.) A unit of electric current, equivalent to an ampere. Obsolete.
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the world > matter > physics > electromagnetic radiation > electricity > electric current > [noun] > unit of measurement > obsolete
weber1871
oersted1879
1879 J. D. Everett Units & Physical Constants xi. 139 The practical unit of current is the current due to an electromotive force of 1 volt working through a resistance of 1 ohm... Its theoretical value is 1 weber per second = 1/10 of the C.G.S. unit of current. In the ‘Testing Instructions of the Indian Telegraph Department’ it is called the Oerstedt.
1885 W. Williams Man. Telegr. 206 The unit current..has already been described as the Ampère or Oerstedt.
2. A unit of reluctance in the cgs electromagnetic system, defined as one gilbert per maxwell. disused.In the International System of Units replaced by the reciprocal henry, equal to approx. 1.26 × 10−8 gilbert per maxwell.
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the world > matter > physics > electromagnetic radiation > electricity > electrically induced magnetism > electromagnetic induction > [noun] > resistance to conduction > unit of
oersted1893
1893 Trans. Amer. Inst. Electr. Engineers 10 364 The four units—gilbert, weber, oersted and gauss—have been suggested by the Committee of the Institute.
1896 M. Maclean Physical Units 92 The committee on Notation of the Chamber of Delegates of the International Electrical Congress of 1893 in Chicago recommended that—unit field intensity, unit magnetic induction, and unit magnetising force be each called a Gauss; unit flux of magnetic force a Weber; unit magneto-motive force a Gilbert; and unit reluctance or magnetic resistance an Oersted.
1931 S. R. Williams Magn. Phenomena i. 46 The oersted of reluctance corresponds to the ohm of resistance.
3. A unit of magnetic field strength in the cgs electromagnetic system, equal to the field strength produced at a distance of one centimetre by a unit magnetic pole or a thin straight wire carrying half an electromagnetic unit (i.e. five amperes) of current; one maxwell per square centimetre. Cf. gauss n.In the International System of Units the oersted is replaced by the ampere per metre, equal to 4π × 10−3 (approx. 0.0126) oersted, one oersted therefore being equal to approx. 79.6 amperes per metre.
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the world > matter > physics > electromagnetic radiation > electricity > electrically induced magnetism > [noun] > field > unit of strength
weber1882
oersted1930
1930 Engineering 25 July 113/2 At the meeting of the International Electrotechnical Commission..it was..recommended that the names of maxwell, gauss, oersted and gilbert should be applied to the C.G.S. units for magnetic flux, flux density, magnetic field intensity and magneto-motive force respectively.
1938 R. W. Lawson tr. G. von Hevesy & F. A. Paneth Man. Radioactivity (ed. 2) ii. 26 By means of deflexion experiments in very strong magnetic fields (23,000 oersteds) a fine structure of the α-particles from thorium C..has been detected.
1963 H. G. Jerrard & D. B. McNeill Dict. Sci. Units 97 The earth's magnetic field has a magnetizing force of the order 0·2 to 0·3 oersted.
1974 Nature 16 Aug. 535/2 Few, if any [geomagneticians] have really cared whether their magnetometers have measured B or H; the gauss, the c.g.s. unit of B, has by usage become totally interchangeable with the oersted, the c.g.s. unit of H.
2000 Nature 14 Sept. 150/3 The coercivity of these FeCo alloys tends to be greater than 5 oersteds, making them unsuitable for magnetic write heads.
This entry has been updated (OED Third Edition, March 2004; most recently modified version published online March 2022).
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n.1879