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The hot wire barretter was a demodulating detector, invented in 1902 by Reginald Fessenden, that found limited use in early radio receivers. In effect it was a highly sensitive thermoresistor developed to permit the reception of amplitude modulated signals, something that the coherer (the standard detector of the time) could not do.〔''History of Wireless'' Tapan K. Sarkar, Robert Mailloux, Arthur A. Oliner, Magdalena Salazar-Palma, Dipak L. Sengupta ISBN 978-0-471-78301-5 January 2006, Wiley-IEEE Press page 369〕 The first device used to demodulate audio signals, it was later superseded by the electrolytic detector, also generally attributed to Fessenden. The barretter principle is still used as a detector for microwave radiation, similar to a bolometer.〔IEEE Std. 100 Dictionary of IEEE Standards Terms, 7th Ed. ISBN 0-7381-2601-2〕 ==Description and construction== An extremely fine platinum wire, about in diameter, is embedded in the middle of a silver tube having a diameter of about . This compound wire is then drawn until the silver wire had a diameter of about ; as the platinum wire within it is reduced in the same ratio, it is drawn down to a final diameter of . The result is called Wollaston wire. The silver cladding is etched off a short piece of the composite wire, leaving an extremely fine platinum wire; this is supported, on two heavier silver wires, in a loop inside a glass bulb. The leads are taken out through the glass envelope and the whole device is put under vacuum and then sealed. 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「Hot wire barretter」の詳細全文を読む スポンサード リンク
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