cathode-ray tube


Cathode-ray tube

cathode-ray tube (CRT), special-purpose electron tube in which electrons are accelerated by high-voltage anodes, formed into a beam by focusing electrodes, and projected toward a phosphorescent screen that forms one face of the tube. The beam of electrons leaves a bright spot wherever it strikes the phosphor screen. To form a display, or image, on the screen, the electron beam is deflected in the vertical and horizontal directions either by the electrostatic effect of electrodes within the tube or by magnetic fields produced by coils located around the neck of the tube. Some CRTs can produce multiple beams of electrons and have phosphor screens that are capable of displaying more than one color. CRTs have been used in television receivers, computer terminals and monitors, automated teller machines, oscilloscopes, radar displays, and other devices, but liquid crystal displays are now typically used.

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