A device for producing electron beams. A heated cathode produces electrons by thermionic emission. These are attracted away by a nearby positively-charged grid, which regulates the number of electrons and hence beam brightness. Electric fields then accelerate and focus the beam. It is an essential component of television tubes, electron microscopes, and cathode ray tubes.
An electron gun is a component that produces an electron beam that has a precise kinetic energy, being used in all TVs and monitors which use cathode ray tube technology, and in other instruments, eg.
It is formed of several parts: a hot cathode, which is heated to create a stream of electrons via thermionic emission, electrodes generating an electric field which focus the beam (eg.
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. Each stream travels through a shadow mask where the electrons 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 being a combination of these three primary colours (including white).
Ionisation
An electron gun can be used to ionise particles by adding or removing electrons from the atom.
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