Summary
This valve appears to be a replacement for the Marconi Osram DE7. The DE7 was introduced in 1924 and was obsolete at the time this sample was manufactured (1936 or later). The DE7 was a space-charge tetrode designed to work at very low anode voltage (6 - 15 V).
Manufacturer: Amalgamated Wireless Valve Co., Sydney, Australia.
AWV had an agreement with MOV on valve manufacture and did manufacture valves labeled Osram for the Australian market. According to Fin Stewart who was asked about this valve, it was probably made in about 1936 based on the style of printing on the base. It would not be any earlier than that because there is an excise stamp and these only started in 1936.
The base of the valve is labelled 'Radiotron', which was AWV's brand and since they made the valve even though it was not their design. It is assumed that they felt entitled to brand it as such.
Presumably these were made to keep some piece of military equipment going which used an Osram DE7 valve.
1.8 V directly heated cathode.
Physical Description
Shouldered bulb with 4 pin English style base with side terminal.
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
Amalgamated Wireless Valve Co Pty Ltd (AWV), Sydney, Greater Sydney, New South Wales, Australia, circa 1936
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Inscriptions
Bulb: DE7 Base: Radiotron/Made in Australia/1/4
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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
113 mm (Length), 45 mm (Outside Diameter)
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References
Fin Stewart, History of GEC and the Marconi Osram Valve. PP 43, 46 (pictures) & 78 (data).
[Book] Stewart, Finlayson (Fin). 1995. Illustrated History of Philips Radio Valves to 1935., 1995, 43, 46, 78 Pages
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Keywords