File:First Audion amplifier 1914.jpg
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![File:First Audion amplifier 1914.jpg](https://upload.wikimedia.org/wikipedia/commons/thumb/5/5e/First_Audion_amplifier_1914.jpg/391px-First_Audion_amplifier_1914.jpg?20210502183725)
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Electronic amplifier built by Lee De Foirest in 1914
Summary
[edit]DescriptionFirst Audion amplifier 1914.jpg |
English: One of the first Audion amplifiers built by the inventor of the Audion vacuum tube, Lee De Forest, around 1914. The Audion, the first triode, was the first electronic tube that was able to amplify. Although invented in 1906, the amplifying ability of the Audion was not recognized until 1911-1912, so this was one of the first amplifiers. It appears in a paper by De Forest demonstrating to his fellow engineers that the Audion was not just a radio detector but also had the ability to amplify a signal. This is a three-stage transformer coupled audio amplifier. The Audion bulbs are visible on the front. Audions were always mounted upside-down, with the fragile filament loop hanging down, to prevent it from sagging when hot and touching the grid. Next to each tube are two rotary switches, one to control the filament current and one the plate voltage. The plate voltage between 15 and 40 volts, had to be carefully controlled. The primitive Audion was not completely evacuated, but had some gas in the tube, so if the plate voltage exceeded about 40 volts the gas would break down and ionize, emitting a "blue glow" discharge; which could damage the tube. The tube had a voltage gain of up to 5, so this amplifier had a maximum gain of about 125. |
Date | |
Source | Downloaded 03-26-2013 from Lee De Forest The Audion - Detector and Amplifier in Proc. of the Institute of Radio Engineers ( Institute of Radio Engineers, NY) Vol. 2, No. 1, March 1914, p.23, fig. 5 on Google Books |
Author | Lee De Forest |
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[edit]Public domainPublic domainfalsefalse |
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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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current | 18:37, 2 May 2021 | ![]() | 1,556 × 2,383 (662 KB) | Materialscientist (talk | contribs) | FFT |
03:32, 6 August 2015 | ![]() | 1,556 × 2,383 (400 KB) | Chetvorno (talk | contribs) | User created page with UploadWizard |
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