File:Precision cat's whisker detector.jpg
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Summary
| Description |
English: A precision crystal detector (sometimes called a cat's whisker detector) from around 1914, an obsolete radio component used in unamplified crystal radio receivers. This type was a professional unit used in sensitive receivers in wireless telegraphy stations. The vertical needle on the right gently touches the face of a crystal of iron pyrite (iron sulfide, FeS2, Fool's gold) contained in the cylindrical metal capsule below it, forming a diode which is used to rectify the received radio signal. Only certain sites on the crystal's face functioned as rectifying junctions, so the device had to be adjusted by trial and error to find a "sweet spot" before each use. The crude device was very sensitive to the contact between needle and crystal, so the spring loaded micrometer screw on the left can be used to adjust the pressure precisely. |
| Date | |
| Source | Downloaded 2009-11-08 from Alfred Powell Morgan (1914) Wireless Telegraph Construction for Amateurs, 3rd Ed., p. 134, fig. 106 on Google Books |
| Author | Alfred Powell Morgan |
| Permission (Reusing this file) |
Public domain in USA - published in USA prior to 1923 |
Licensing
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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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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.
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File history
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| Date/Time | Thumbnail | Dimensions | User | Comment | |
|---|---|---|---|---|---|
| current | 11:18, 3 May 2021 | | 890 × 586 (246 KB) | Materialscientist | FFT |
| 18:21, 10 November 2009 |  | 890 × 586 (124 KB) | Chetvorno | {{Information |Description={{en|A Wikipedia:cat's whisker detector, an antique radio component used in early crystal radios, from a 1914 book on wireless telegraphy. This was a precision micrometer type. The vertical needle on the right gently touc |
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