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12 Volt Fleming Valve, by Royal Ediswan, London, c. 1905
Inventory Number: 77499
Number of documents: 2
Document Type: Miscellaneous Note
Document Heading: Manufacturer Details - Ediswan
Text:
Ediswan, the trade name of the Edison and Swan United Electric Light Company Limited, made this valve for Marconi's Wireless Telegraph Co. Ltd. Joseph Swan, a Briton, and Thomas Edison, the famous American inventor jointly founded the company, as a result of the major court battle they fought over who was the original inventor of the electric light bulb. The company produced all the Marconi valves up to 1919, manufactured at them at their factory in Ponders End, North London.
Some Ediswan valves were marked 'Royal Ediswan' up to 1923.
Document Type: Miscellaneous Note
Document Heading: Technical Details
Text:
A thermionic valve (also known as a vacuum tube) is an electronic device consisting of an arrangement of electrodes in a vacuum within an insulating, temperature-resistant envelope. Basic thermionic valves resembled an incandescent light bulb. Prof. J. A. Fleming, chief scientific advisor to the Marconi Company from 1900, invented the diode, a special kind of thermionic valve, in 1904. The valve was initially experimental, despite its massive advantages over the crude crystal sets: it was more sensitive, could carry speech, and enabled higher speeds of Morse code transmission and reception. These valves led to more compact, mobile, and powerful Wireless Telegraphy sets. A triode is a type of valve with three elements: the filament or cathode, the grid, and the plate or anode. The triode vacuum tube was the first electrical amplification device and still remains in use for amplification purposes.
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