Summary
'Soft' triode used as a detector in radios in the early 1920s. The electrode structure is the same as the UV 201 but the bulb is filled with argon at a pressure of 50 µm of mercury. Gas filled valves were referred to as 'soft', high vacuum valves were called 'hard'. Soft valves were more sensitive detectors at low signal levels but were very fiddly to use and went out of general use by about 1925. 5 volt directly heated cathode.
Physical Description
Conical clear glass bulb with 4 pin UV base with brass shell and ceramic insulation. Mounted on a display block.
More Information
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Collection Names
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Collecting Areas
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Acquisition Information
Donation from E. W. Lindblade, 28 Jan 1942
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Manufacturer
Radio Corporation of America (RCA), United States of America, circa 1923
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Inscriptions
On top of bulb: RCA logo On base: RADIOTRON/UV 200/LICENSED ONLY/TO EXTENT INDI-/CATED ON CARTON. On display block: Identification of valve and brief description of characteristics.
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Brand Names
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Classification
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Category
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Discipline
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Type of item
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Overall Dimensions
105 mm (Height), 44 mm (Outside Diameter)
Not including display block.
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