An electron tube evacuated to such a degree that its electrical characteristics are essentially unaffected by the presence of residual gas or vapour.
- 1904 first tube, a two-element diode, invented and patented by Ambrose Fleming
- 1907 Lee de Forest developed the first triode by adding a grid between the cathode and the anode, this was the first amplifier.
That electrode within a tube which is heated for electron emission or which transfers its heat to a separate cathode for electron emission.
A tube in which the filament heats the cathode to produce electron emission.
The internal capacitances existing between the elements of a vacuum tube.