https://collection.sciencemuseumgroup.org.uk/objects/co467865/one-of-flemings-first-thermionic-diode-valves-1889-thermionic-valve Science Museum Group Collection * Collection * Learning * The group * Visit us Expand child menu + Science Museum + National Science and Media Museum + Science and Industry Museum + National Railway Museum + Locomotion Collection * Search * About * Search * About * Collection * Learning * The group * Visit us Expand child menu + Science Museum + National Science and Media Museum + Science and Industry Museum + National Railway Museum + Locomotion [ ] One of Fleming's first thermionic diode valves, 1889 Made: 1889 in London inventor: John Ambrose Fleming [small_thum] [small_thum] [small_thum] [small_thum] [small_thum] [small_thum] Creative Commons LicenseThis image is released under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 Licence Download Buy this image as a print Buy License this image for commercial use at Science and Society Picture Library License Creative Commons LicenseThis image is released under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 Licence Download Buy this image as a print Buy License this image for commercial use at Science and Society Picture Library License Creative Commons LicenseThis image is released under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 Licence Download Buy this image as a print Buy License this image for commercial use at Science and Society Picture Library License Creative Commons LicenseThis image is released under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 Licence Download Buy this image as a print Buy License this image for commercial use at Science and Society Picture Library License Creative Commons LicenseThis image is released under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 Licence Download Buy this image as a print Buy License this image for commercial use at Science and Society Picture Library License Creative Commons LicenseThis image is released under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 Licence Download Buy this image as a print Buy License this image for commercial use at Science and Society Picture Library License Use this image Use this image Use this image Use this image Use this image Use this image Original thermionic diode valve invented by Sir John Ambrose Fleming, made by the Edison & Swan United Electric Light Science Museum Group Collection (c) The Board of Trustees of the Science Museum Original thermionic diode valve invented by Sir John Ambrose Fleming, made by the Edison & Swan United Electric Science Museum Group Collection (c) The Board of Trustees of the Science Museum Original thermionic diode valve invented by Sir John Ambrose Fleming, made by the Edison & Swan United Electric Light Science Museum Group Collection (c) The Board of Trustees of the Science Museum Original thermionic diode valve invented by Sir John Ambrose Fleming, made by the Edison & Swan United Electric Science Museum Group Collection (c) The Board of Trustees of the Science Museum Three original thermionic valves invented by Sir John Ambrose Fleming, Edison and Swan United Electric Light Company, Science Museum Group Collection (c) The Board of Trustees of the Science Museum Left: Original thermionic diode valve invented by Sir John Ambrose Fleming, made by the Edison & Swan United Electric Science Museum Group Collection (c) The Board of Trustees of the Science Museum Thermionic valve, one of three original examples, by Sir John Ambrose Fleming, London, England, 1904. This valve uses a lamp with a flat concertina wire filament, by Edison & Swan United Electric Company, London, England, 1889. Original thermionic diode valve invented by Sir John Ambrose Fleming, made by the Edison & Swan United Electric Light Company, London, England, 1889. This is one of the original valves used by Sir John Ambrose Fleming in his research during 1889 into the 'Edison Effect' - where an extra electrode connected to the positive end of the filament inside a carbon filament light bulb would create a small but measurable charge. After being stored in a cupboard for several years, the valves were once again put to use in 1904 during some experiments by Fleming, resulting in the invention of the two-electrode valve. A few years later American engineer Lee de Forest improved on Fleming's valve to invent the audion, or triode, which could amplify as well as detect signals. A long and painful legal battle over patent rights for the thermionic valve followed between Fleming and de Forest. On display Science Museum: Information Age Gallery: Broadcast If you are visiting to see this object, please contact us in advance to make sure that it will be on display. Related people * Thomas Alva Edison Details Category: Electronic Components Object Number: 1925-814/3 Materials: glass, metal (unknown), textile and wood (unidentified) type: thermionic valve taxonomy: + component - object credit: Sir John Ambrose Fleming Cite this page [Science Museum Group] Rights We encourage the use and reuse of our collection data. 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