| a device consisting of the cathode ray tube, which emits electrons, and a surrounding electrostatic or electromagnetic apparatus, which controls, focuses, and accelerates the stream of electrons (electron beam). |
| electron gun n. The electrode, especially in a cathode-ray tube, that produces a beam of accelerated electrons. |
| electron gun
The part of a cathode-ray tube that emits a narrow beam of electrons, consisting of a cathode, control grids, and usually a heater. Electrons are emitted from the cathode, which is typically heated by electric current to give the electrons escape energy. The electrons are then focused into a beam by the electric fields of the control grids. |
electron gun
electrode structure that produces and may control, focus, and deflect a beam of electrons, as in a television picture tube (see ), where the beam produces a visual pattern on the tube's screen. The source of the electron beam is the cathode, a flat metal support covered with oxides of barium and strontium. When heated by a coil behind the support, these oxides emit electrons, which are drawn toward a positively charged sleeve (first anode) that is contoured to allow the electron beam to flow within the inside diameter. The beam is then electrostatically constricted and collimated by a metal disk with a hole (the control electrode) before it is directed to strike a phosphor-coated screen
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