Audion
Sign in to savethumb|Triode Audion [[vacuum tube from 1908. The filament (which was also the cathode) was at the lower left inside the tube, but has burned out and is no longer present. The filament's connecting and supporting wires are visible. The plate is at the middle top, and the grid is the serpentine electrode below it. The plate and grid connections leave the tube at the right.]]
Article
7 sectionsContents
- History
- Patents and disputes
- Kenotron and Pliotron
- Applications and use
- References
- Further reading
- External links
thumb|Triode Audion [[vacuum tube from 1908. The filament (which was also the cathode) was at the lower left inside the tube, but has burned out and is no longer present. The filament's connecting and supporting wires are visible. The plate is at the middle top, and the grid is the serpentine electrode below it. The plate and grid connections leave the tube at the right.]]
The Audion is an electronic detecting or amplifying vacuum tube invented by American electrical engineer Lee de Forest as a diode in 1906. Improved, it was patented as the first triode in 1908, consisting of an evacuated glass tube containing three electrodes: a heated filament (the cathode, made out of tantalum), a grid, and a plate (the anode). It is important in the history of technology because it was the first widely used electronic device that could amplify. A low power signal at the grid could control much more power in the plate circuit.