Plate electrode

Cutaway diagram of a triode vacuum tube, showing the plate (anode)
The plate from an EL84 pentode tube widely used in audio amplifiers in 1960s era radios and televisions, and still used in guitar amplifiers
Schematic symbol used in circuit diagrams for vacuum tube, showing plate

A plate, usually called anode in Britain, is a type of electrode that forms part of a vacuum tube.[1] It is usually made of sheet metal, connected to a wire which passes through the glass envelope of the tube to a terminal in the base of the tube, where it is connected to the external circuit. The plate is given a positive potential, and its function is to attract and capture the electrons emitted by the cathode. Although it is sometimes a flat plate, it is more often in the shape of a cylinder or flat open-ended box surrounding the other electrodes.

  1. ^ Thomas A. Edison U.S. patent 307,031 "Electrical Indicator", Issue date: 1884