electron gun

noun Electronics, Television.

1. a device consisting of the cathode ray tube, which emits electrons, and a surrounding electrostatic or electromagnetic apparatus, which controls, focuses, and accelerates the stream of electrons (electron beam).

noun

1. a heated cathode with an associated system of electrodes and coils for producing and focusing a beam of electrons, used esp in cathode-ray tubes

1. The part of a cathode-ray tube that emits a narrow beam of electrons, consisting of a cathode, control grids, and usually a heater. Electrons are emitted from the cathode, which is typically heated by electric current to give the electrons escape energy. The electrons are then focused into a beam by the electric fields of the control grids.