Catalogue
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Osram-GEC Radio Valve Type R4, by Osram-GEC, England, 1917
Inventory Number: 96640
Date: 1917
Maker Details: Attributed to Osram-GEC.
Inscription: None
Size: 75 mm in overall height (excluding base)
Materials: Teak?, glass, copper?, tungsten, assorted metals.
Notes:
Osram-GEC Soft Triode Radio Valve Type R4, with bulb-shaped glass exterior, brass fittings and a teak? mounting. With cylindrical anode threaded by helical grid with an interior single-strand wire filament, made of tungsten. In use filament would burn brightly similarly to a light bulb. This particular example was used by the Admiralty as a receiving valve, and technically should be given the designation Type NR4, but is referred to under its common designation of Type R4.
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