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Description
By the time this 1914 de Forest Audion was made for the U.S. Navy, the triode vacuum tube served as an amplifier of audio and an oscillator for transmitting. This globe-shaped Audion was handmade in the shop of H. W. McCandless and Co, New York, in 1914. Although McCandless had been using the globe shape since about 1908, it is the bulb's double "Hudson" filament that dates it to 1914. The Hudson technique, developed that year, required a tungston wire to be wrapped around a tantalum filiament (later the tantalum filament was dipped). In this bulb, both tungsten and tantalum filament are, remarkably, intact. Hundreds of tubes like this one were sold to the U.S. Navy between 1914-1915 (not for commercial use), all made by McCandless. On the exterior of the candelabra base, the second filament is protected by string and rubber band, suggesting the second filament was not used. The single plate, or wing, does not have clipped edges. Two attached paper labels note its patent number and date, and that its production was not for commercial use.
Type
image
Identifier
EDAA812E-7E61-461D-A8E7-742031533247 2003-1-1
Subject
Radio industry Audion Nineteen tens De Forest, Lee
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