cath·ode-ray tube (k th  d-r  )n. Abbr. CRT A vacuum tube in which a hot cathode emits electrons that are accelerated as a beam through a relatively high voltage anode, further focused or deflected electrostatically or electromagnetically, and allowed to fall on a phosphorescent screen. |   |
cathode-ray tube
Noun
a valve in which a beam of electrons is focused onto a fluorescent screen to produce a visible image, used in television receivers and visual display units
| cathode-ray tube A sealed tube in which electrons are emitted by a heated, negatively charged element (the cathode), and travel in a beam toward a positively charged plate (the anode). Depending on the properties of the plate and the speed of the electrons, cathode-ray tubes can generate x-rays, visible light, and other frequencies of electromagnetic radiation. They are central to most television screens, in which the electron beams form images on a phosphor-coated screen. A Closer Look Cathode-ray tubes (CRTs), also called electron-ray tubes, provide the visual display in such devices as conventional television sets, computer monitors, hospital heart monitors, and laboratory oscilloscopes. CRTs are generally made of funnel-shaped glass vacuum tubes. At the larger end of the tube is a phosphor-coated screen, and at the other end is an electron gun. The gun consists of a heated cathode, or negative electrode, which emits electrons, and a control grid, which controls the intensity of the beam of electrons to vary the brightness of the image. The gun directs the electron beam, or cathode ray, toward the screen, where a positively charged anode attracts the electrons. Outside the tube, coils creating a magnetic field or plates creating an electric field both focus and steer the beam. Wherever the beam strikes the screen, it causes the phosphors to glow. Shapes and images can be formed by manipulating the beam so that its focal point on the screen sweeps across it in various paths and with different brightness. In most CRTs, the beam follows a zigzag path that covers the entire screen many times per second. Color screens use three separate beams that strike three individually colored phosphor cells (having the three primary colors red, blue, and green) that are very close together. The color combinations appear to the eye (at a distance to the screen) as one point of a single color. |  |
ThesaurusLegend: Synonyms Related Words Antonyms
| Noun | 1. | cathode-ray tube - a vacuum tube in which a hot cathode emits a beam of electrons that pass through a high voltage anode and are focused or deflected before hitting a phosphorescent screen computer, computing device, computing machine, data processor, electronic computer, information processing system - a machine for performing calculations automatically Crookes tube - the original gas-discharge cathode-ray tube electron gun - the electrode that is the source of electrons in a cathode-ray tube or electron microscope; consists of a cathode that emits a stream of electrons and the electrostatic or electromagnetic apparatus that focuses it gas-discharge tube - a tube in which an electric discharge takes place through a gas kinescope, picture tube, television tube - a cathode-ray tube in a television receiver; translates the received signal into a picture on a luminescent screen cathode-ray oscilloscope, CRO, oscilloscope, scope - electronic equipment that provides visual images of varying electrical quantities CRT screen, screen - the display that is electronically created on the surface of the large end of a cathode-ray tube television system, television - a telecommunication system that transmits images of objects (stationary or moving) between distant points |
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