Original thermionic valve devised by Sir John Ambrose Fleming in 1904, using a filment lamp made by the Edison & Swan United Electric Light Company, London, in 1889
Original thermionic valves invented by Sir John Ambrose Fleming, made by the Edison & Swan United Electric Light Company, London, 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.
- Electronic Components
- Object Number:
- thermionic emission
- Sir Ambrose Fleming
- Permanent collection
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