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File:De Forest Audion radiophone.jpg

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English: The Type RJ Oscillion radiotelephone, by the De Forest Wireless Telegraph Co. around 1916, an early, low power AM (voice) radio transmitter using an Audion, the first amplifying vacuum tube. Built by Lee De Forest, who invented the Audion in 1906. The amplifying and oscillation ability of the Audion was not discovered until 1912, so this is one of the earliest tube radio transmitters. It uses a carbon microphone (top center) in the antenna lead to modulate the RF signal going to the antenna. The slender Audion tube is mounted on the front panel under the microphone, upside down, with the U shaped filament in the tube hanging down, so it wouldn't touch the grid electrode. The multiposition switch (upper left) adjusts the tube plate voltage, while the potentiometer (upper right) adjusts the filament current.
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Source Downloaded 23 September 2013 from "Wireless Telegraphy and Telephony", The New International Encyclopaedia, 2nd Ed., Dodd Mead and Co., New York, 1916, Vol. 23, plates facing p. 712 on Google Books
Author Unknown authorUnknown author

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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.
United States
United States
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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current17:39, 25 September 2013Thumbnail for version as of 17:39, 25 September 2013521 × 755 (53 KB)Chetvorno (talk | contribs)User created page with UploadWizard

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