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I noticed that the RCA tube manual doesn't specify, for each tube, exactly what are the composition and precise dimensions of the filament. They just have some general remarks about the kinds of materials used in filaments. But I know from other sources that the FP-400 tube had a filament made of pure tungsten and the length and diameter of the filament were also given.

So, is this kind of information available for other tubes?

Likewise, studies (including detailed graphs) of resistivity of tungsten as a function of temperature have been published. Is there any other filament material for which such data is available?

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Ignorantly,
Allan Adler 
* Disclaimer: I am a guest and *not* a member of the MIT CSAIL. My actions and
* comments do not reflect in any way on MIT. Also, I am nowhere near Boston.
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Allan Adler
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It wouldn't be there. The manual was for the end user, not for the manufacturer of tubes. It's no different from any transistor datasheet, where you have no control over what's inside so what's inside is pretty irrelevant.

Michael

Reply to
Michael Black

Most receiving tubes have indirectly heated cathodes, so tube manufacturers are free to construct the filament in whatever way they feel is best, as long it operates at the required voltage and current, and heats the cathode. Different manufacturers could very well use different heater designs for any given tube type.

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Peter Bennett, VE7CEI  
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Peter Bennett

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