File:Blondel coherer and Guarini decoherer.jpg
Size of this preview: 562 × 599 pixels. Other resolutions: 225 × 240 pixels | 450 × 480 pixels | 663 × 707 pixels.
Original file (663 × 707 pixels, file size: 159 KB, MIME type: image/jpeg)
 | This is a file from the Wikimedia Commons. Information from its description page there is shown below. Commons is a freely licensed media file repository. You can help. |
Summary
| Description |
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
 |
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.
|
 |
 |
This image might not be in the public domain outside of the United States; this especially applies in the countries and areas that do not apply the rule of the shorter term for US works, such as Canada, Mainland China (not Hong Kong or Macao), Germany, Mexico, and Switzerland. The creator and year of publication are essential information and must be provided. See Wikipedia:Public domain and Wikipedia:Copyrights for more details.
|
| Annotations | This image is annotated: View the annotations at Commons |
File history
Click on a date/time to view the file as it appeared at that time.
| Date/Time | Thumbnail | Dimensions | User | Comment | |
|---|---|---|---|---|---|
| current | 15:58, 2 May 2021 | | 663 × 707 (159 KB) | Materialscientist | FFT |
| 18:53, 30 April 2010 |  | 663 × 707 (75 KB) | Chetvorno | {{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.}} | |
File usage
The following pages on the English Wikipedia use this file (pages on other projects are not listed):
Global file usage
The following other wikis use this file:
