Electron gun
From Free net encyclopedia
Image:Egun.jpg An electron gun is a component that produces an electron stream that has a precise kinetic energy, being used in all TVs and monitors which use cathode ray tube technology, and in other instruments, eg. electron microscopes and at the beginning of linear particle accelerators.
It is formed of two parts: a hot cathode, which is heated to create a stream of electrons via thermionic emission, and electrodes generating an electric field, which accelerates the electrons towards the anode.
Most colour CRTs (such as is used in a colour television set) are made up of three electron guns, each one producing a different stream of electrons and which stream electrons through a shadow mask where the stream from each electron gun will impinge upon either a red, green or blue phosphor to light up a colour dot of a pixel of the screen, the resultant colour (or white) a combination of these three primary colours.