English: One of the first triodevacuum tubes, manufactured around World War 2 by Western Electric, the manufacturing arm of American Telephone and Telegraph (AT&T) Lee De Forest, the inventor of the triode, sold the rights to the triode to Western Electric in 1913. It consists of an evacuated bulb with three electrodes: a heated filament, grid, and plate The filament is in the center of the tube. The two connected grids cosisting of square screens of wire are visible on either side of the filament. The two square plates are outside the grids. When heated by a separate current the filament released electrons, which flowed from the filament in the center through the grids to the positively charged plates. A small variable voltage on the grid could control the much larger current from filament to plate, allowing the tube to amplify weak signals in radio receivers.
Date
before 1922
date QS:P,+1922-00-00T00:00:00Z/7,P1326,+1922-00-00T00:00:00Z/9
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