Summary
General purpose triode. This type was released in 1922 as a dull-emitting version of the R valve, hence the DER designation. It continued in production with various bulb styles for about ten years. The triangular label on this example indicates that it was made in or after 1930. Used as a Class A audio amplifier.
Manufacturer: MO Valve Company, England.
1.8 V directly heated cathode.
Physical Description
Conical bulb with 4 pin European style base.
More Information
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Collection Names
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Collecting Areas
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Acquisition Information
Donation from Australian Wireless Valve Co (AWV Co), 23 Feb 1972
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Manufacturer
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Inscriptions
Bulb: Made and Patented in England/DER Transfer on bulb: /Marconi/(MWTC logo)
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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
93 mm (Length), 46 mm (Outside Diameter)
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References
[Book] Stewart, Finlayson (Fin). 1995. Illustrated History of Philips Radio Valves to 1935., 1995, 43, 48 & 59 Pages
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Keywords