Cathode rays are a stream of high-speed electrons emitted from the heated cathode of a vacuum tube. In a video monitor, the electron beam is focused and diverted by [electric field]?s to scan the surface at the opposite end of the vacuum tube which is lined with [phosphorescent material]?. When the high-speed electrons hit the lining, light is emitted. The video signal is used to control the intensity and scanning position of the electron beam to form a video image on the TV screen.
CRTs have a pronounced triode characteristic which leads them to have a pronounced [gamma response]?. Fortuitously, this functioned as a form of contrast? compression in early television systems, and this [gamma response]? exists today in all digital video systems.
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