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This table shows some of the inter-relatedness of the various
major manufacturers of valves in the U.K. prior to 1930. Links
lead to related pages. See also: National Valve Museum / Valve Technology Timeline . |
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Edison Electric Co. and Swan Electric lighting Co. amalgamate
to form Edison Swan United Electric Co. Western Electric Co. |
Edison effect |
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General Electric Co. | |
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British Thompson Houston Ltd. Alfred Charles Cossor sets up business as a scientific glassware maker |
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Wireless Signal and Telegraph Co. | J J Thompson discovers the electron |
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Marconi Wireless Telegraph Co. | |
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O W Richardson Emission Theory |
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Wehnhelt's oxide cathode | |
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Fleming valve | |
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DeForest Audion | |
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A C Cossor Ltd. Formed | Tungsten Filament |
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Round soft valves | |
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Langmuir dull emitter | |
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French TM Langmuir Pliotron |
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British Thompson Houston Ltd. "BTH" Edison Swan Co. "EDISWAN", "Royal EDISWAN" |
R-type |
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Marconi's Wireless Telegraph Co. English Electric Co. Ltd. "Osram" Metropolitan-Vickers Co. Ltd "COSMOS" |
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Marconi's Wireless Telegraph Co.
- Transmitting valves Marconi-Osram Valve Co. "MARCONI VALVE" Capt. S R Mullard joins the Z Electric Lamp. Co. |
Tetrode invented |
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M-O Valve Co. "MARCONI VALVE" Mullard Radio Valve Co. "MULLARD" |
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First dull emitters sold | |
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Western Electric "WECO" | |
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Edison Swan Electric Co. "EDISWAN" N V Phillips Gloelampenfabriken Electron Company Ltd. "SIX-SIXTY" |
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Phillips obtains 50% holding in Mullard Radio Valve Co. | Azide process and other oxide cathodes |
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M-O Valve Co. "MARCONI", "OSRAM" British Thompson Houston Ltd. "MAZDA" Standard Telephones and Cables "STC", "STANDARD" |
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Mullard gains control of Electron Co. Ltd. "SIX-SIXTY" | Pentode invented |
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Phillips obtains full control of Mullard Radio Valve Co. | Tetrode marketed |
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BTH, Edison-Swan and Metro-Vickers form Associated Electrical Industries | Pentode marketed |
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The Gramophone Co. Ltd. | |
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Electrical amd Musical Industries. "EMI" | |
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EMI "MARCONI", "OSRAM", "GEC" "MAZDA", "BRIMAR", "EDISWAN" "MULLARD", "EVERREADY", "COSSOR", "STANDARD" |