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Re: Filament resistance numbers



The alloy you expect to find in a coiled-coil lamp is a 1% thoria tungsten.
The thoria provides increased resistance to hot-sagging apparently.
(Enc Brit 15th ed.)

Thoriated tungsten was used for vacuum tube cathodes. The thorium
lowered the work function of the metal, enhancing emission of
electrons. Someone else in the group gave the recipe for light
bulb filaments, a ductile tungsten copper alloy which was then
purged of its copper by heating.

Could it be that the Brits got their recipes mixed up? They had
Herbert Dingle write their relativity article. Herbert Dingle
believed that the twin paradox proved relativity was wrong! I
have never quite trusted the Encyclopaedia Britanica since then.

Leigh