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| From The Saga of The Vacuum Tube) |
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| The type N valve came in two versions as explained
in the image. The type 27 receiver used one of these N valves as the high
frequency amplifier. The N valve operated with a filament current of 2.5
amps with 40 to 80 Volts on the anode. (From The Saga of The Vacuum
Tube) |
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| Closeup of the type N valve with Edison
style screwbase. (Photo courtesy History of Science Museum,
Oxford , England). |
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| Closeup of type N valve with Ediswan
style bayonet base. (Photo courtesy of the Science Museum in London,
England) |