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
這一媒體文件在美國屬於公有領域。這可用於版權過期的美國作品,通常這些作品發表於1929年1月1日之前。查看這個頁面可以獲取到更多的解釋。

United States
United States
這一圖片在美國以外可以沒有處於公有領域,特別是對美國作品不適用較短期限法則的國家,如加拿大、中國大陸(不含香港及澳門)、德國、墨西哥和瑞士。作品的作者和發表時間是關鍵信息,並且必須提供。參見 維基百科:公有領域維基百科:版權信息以獲取更多細節。

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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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