File:Two crystal contact detector 1919.png
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![File:Two crystal contact detector 1919.png](https://upload.wikimedia.org/wikipedia/commons/thumb/1/19/Two_crystal_contact_detector_1919.png/315px-Two_crystal_contact_detector_1919.png?20180715014010)
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Captions
A diagram of a crystal detector from 1920
Summary
[edit]DescriptionTwo crystal contact detector 1919.png |
English: Cutaway drawing of a crystal detector used as a demodulator in early crystal radios. It consists of crystalline pieces of two different minerals held in brass cups with their surfaces pressed against each other by the thumbscrew. The two crystals form a crude semiconductor diode. Different combinations of crystals could be used: the most common was zincite and chalcopyrite, called a "Perikon" detector, but the text suggests a combination of zincite and tellurium was a more sensitive detector. The detector was built as a plugin unit so different detectors could be quickly switched in and out to find the most sensitive. The crystal receivers which were used before vacuum tube receivers superseded them around 1920 did not have the ability to amplify the radio signal, so the sensitivity of the crystal detector mainly determined the reception range. Many different crystals were tried in an effort to improve sensitivity. |
Date | |
Source | Retrieved 14 July 2018 from Rupert Stanley (1919) Textbook on Wireless Telegraphy Vol. 1: General Theory and Practice, Longmans Green and Co., New York, p. 316, fig. 153 on Google Books |
Author | Rupert Stanley |
Licensing
[edit]Public domainPublic domainfalsefalse |
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This work is in the public domain in the United States because it was published (or registered with the U.S. Copyright Office) before January 1, 1929.
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Note: This tag should not be used for sound recordings.PD-1923Public domain in the United States//commons.wikimedia.org/wiki/File:Two_crystal_contact_detector_1919.png |
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current | 01:40, 15 July 2018 | ![]() | 408 × 775 (90 KB) | Chetvorno (talk | contribs) | User created page with UploadWizard |
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Horizontal resolution | 28.35 dpc |
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Vertical resolution | 28.35 dpc |
File change date and time | 00:49, 15 July 2018 |
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