Summary
A general purpose low mu triode intended for use as an audio or RF amplifier at power levels up to 1.3 watt in class A and higher powers in class B and C.
This valve would have been manufactured for use by the Postmaster General's Department (PMG) for use in their carrier telephone systems.
Manufactured by: Standard Telephones and Cables. The listing of the Australian patent on the bulb suggests that it was made by STC Australia (Alexandria, NSW).
It is the STC version of the Western Electric 205E. It has a 4.5 volt directly heated cathode.
Physical Description
Spherical glass bulb with exhaust tip on top. 4 pin UV style base with metal shell.
More Information
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Collection Names
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Collecting Areas
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Acquisition Information
Purchase
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Manufacturer (Probable)
Standard Telephone & Cables Ltd (STC Ltd), Alexandria, New South Wales, Australia, 1930-1940
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Inscriptions
Bulb: M4205E/AUSTRALIAN/PATENT No/1252-21/7.4.21 Base: STANDARD TELEPHONE & CABLES/PATENTED IN GREAT BRITAIN/(patent numbers)/4205E
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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
107 mm (Length), 59 mm (Outside Diameter)
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Keywords