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Manganin is a trademarked name for an alloy of typically 86% copper, 12% manganese, and 2% nickel. It was first developed by Edward Weston in 1892, improving upon his Constantan (1887). Manganin foil and wire is used in the manufacture of resistors, particularly ammeter shunts, because of its virtually zero temperature coefficient of resistance value〔(Manganin spec. sheet )〕 and long term stability. Several Manganin resistors served as the legal standard for the ohm in the United States from 1901 to 1990.〔(Stability of Double-Walled Manganin Resistors )〕 Manganin wire is also used as an electrical conductor in cryogenic systems, minimizing heat transfer between points which need electrical connections. Manganin is also used in gauges for studies of high-pressure shock waves (such as those generated from the detonation of explosives) because it has low strain sensitivity but high hydrostatic pressure sensitivity. == History == In 1887 Edward Weston discovered that metals can have a negative temperature coefficient of resistance, inventing what he called his "Alloy No. 2." It was produced in Germany where it was renamed "Constantan".〔 https://archive.org/stream/chronologicalhis00natirich/chronologicalhis00natirich_djvu.txt A CHRONOLOGICAL HISTORY OF ELECTRICAL DEVELOPMENT FROM 600 B.C.; NATIONAL ELECTRICAL MANUFACTURERS ASSOCIATION; 155 EAST 44th STREET; NEW YORK 17, N. Y.; Copyright 1946; National Electrical Manufacturers Association; Excerpts from this book may be used without permission 〕 In 1892 Weston had finally completed his discovery of an alloy of copper, nickel, and manganese prepared by a complicated series of heat-treatments. In May, 1893, he received a basic patent on the composition, manufacture, and use of the material for electrical resistors. Production was carried out in Germany, and it became known as "Manganin". The availability of a practical conductive metal with an extremely constant resistance over the range of ordinary temperatures was a great advance in electrical technology and equipment design, but Weston did not receive general recognition for this. 〔 https://archive.org/stream/measureforgreatn001419mbp/measureforgreatn001419mbp_djvu.txt A Measure for Greatness; A SHORT BIOGRAPHY OF EDWARD WESTON; by DAVID O. WOODBURY, A.B., B.S., M.S.; McGRAW-HILL BOOK COMPANY, INC.; New York, Toronto, London; 1949 〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Manganin」の詳細全文を読む スポンサード リンク
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