File:First Audion amplifier 1914.jpg

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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.
日期
来源 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
作者 Lee De Forest

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Public domain
Public domain
这个媒体文件在美国属于公有领域。这适用于版权过期的美国作品,通常因为其首次出版于1929年1月1日之前,或即便当天或以后出版,其并未包含版权通告或获得版权回溯。查看这个页面可以获取到更多的解释。

United States
United States
这个图片在美国以外可能尚未处于公有领域;尤其在对美国作品不适用较短期限法则的国家和地区,如加拿大、中国大陆(不含香港及澳门)、德国、墨西哥和瑞士。创作者和发表年份是关键信息,因此必须提供。参见维基百科:公有领域维基百科:版权信息以获取更多细节。

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Electronic amplifier built by Lee De Foirest in 1914

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3月 1914格里历

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当前2021年5月2日 (日) 18:372021年5月2日 (日) 18:37版本的缩略图1,556 × 2,383(662 KB)MaterialscientistFFT
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