A TRIODE is an electron tube with three electrodes namely a cathode, control grid and anode. This was the first amplifying tube and was invented by Lee de Forest in 1905 when he placed a grid in a diode. By suitably biasing the grid * with respect to the cathode it is possible to control the density of the electron stream from the cathode which reaches the anode. Thus the grid voltage controls the anode current.
A GRID is an electrode placed between the cathode and the anode of an electron tube and through the interstices of which the main electron stream of the tube passes.
An ELECTRON TUBE is a general term for an evacuated or gas-filled envelope, containing electrodes and in which conduction occurs by virtue of2 electrons or tons which move in a controlled manner according to the voltages or currents applied to the electrodes.
CONDUCTIVITY is a term expressing the ability of a material to carry an electric current. The conductivity of metals, for example, is better, i. e. higher than that of non-metals.
ПРИМЕЧАНИЯ
1 by suitably biasing the grid — соответственно изменяя (букв, смещая) напряжение на сетке
2by virtue of — благодаря