File:Blondel coherer and Guarini decoherer.jpg
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[edit]DescriptionBlondel coherer and Guarini decoherer.jpg |
English: A coherer, a crude radio detector used in the first radio receivers from about 1895 to 1906 during the wireless telegraphy era. This example was built by radio researcher Emile Guarini Foresio. It is a glass tube (right) containing metal powder between two electrodes. When a radio signal is applied between the electrodes, the metal powder coheres (clumps together) causing the tube to conduct electricity. The coherer is attached to a DC circuit (not shown) which makes a mark on a paper tape to record the Morse code radio message. Because the coherer remained in its conducting state after the radio wave stopped, the device includes a "decoherer" or "tapper" (left) which uses an electromagnet-activated arm to tap the coherer, agitating the powder, to return the device to its nonconducting state in preparation to receive another radio signal. |
Date | |
Source | Downloaded 2010-03-04 from A. Frederick Collins (1904) "The Metamorphosis of Wireless Telegraph Apparatus" in The Engineering Magazine, Vol. 27, No.4 (June 1904) p.376, fig. 24 on Google Books |
Author | Archie Frederick Collins |
Permission (Reusing this file) |
Public domain in USA - Published in USA prior to 1923 |
Licensing
[edit]Public domainPublic domainfalsefalse |
This media file is in the public domain in the United States. This applies to U.S. works where the copyright has expired, often because its first publication occurred prior to January 1, 1929, and if not then due to lack of notice or renewal. See this page for further explanation.
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Date/Time | Thumbnail | Dimensions | User | Comment | |
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current | 15:58, 2 May 2021 | 663 × 707 (159 KB) | Materialscientist (talk | contribs) | FFT | |
18:53, 30 April 2010 | 663 × 707 (75 KB) | Chetvorno (talk | contribs) | {{Information |Description={{en|A Wikipedia:coherer, a crude radio detector used in the first radio receivers from about 1895 to 1906 during the Wikipedia:wireless telegraphy era. It is a tube containing metal powder between two electrodes.}} | |
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