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vacuum tube meaning

Synonyms of "vacuum tube""vacuum tube" in a sentence
MeaningMobile
  • Noun: vacuum tube  vakyoom t(y)oob
    1. Electronic device consisting of a system of electrodes arranged in an evacuated glass or metal envelope
      - tube, thermionic vacuum tube, thermionic tube, electron tube, thermionic valve

    Derived forms: vacuum tubes

    Type of: electronic device

    Part of: circuit, electric circuit, electrical circuit

    Encyclopedia: Vacuum tube


  • [Electronics]
    An electron tube from which virtually all air and gases are removed. Also see ELECTRON TUBE.

  • [Medicine]
    n : an electronic device in which conduction by electrons takes place through a vacuum within a sealed glass or metal container and which has various uses based on the controlled flow of electrons

  • [Computer]
    <electronics> (Or tube, vacuum tube, UK: valve, electron valve, thermionic valve, firebottle, glassfet) An electronic component consisting of a space exhausted of gas to such an extent that electrons may move about freely, and two or more electrodes with external connections. Nearly all tubes are of the thermionic type where one electrode, called the cathode, is heated, and electrons are emitted from its surface with a small energy (typically a Volt or less). A second electrode, called the anode (plate) will attract the electrons when it is positive with respect to the cathode, allowing current in one direction but not the other.

    In types which are used for amplification of signals, additional electrodes, called grids, beam-forming electrodes, focussing electrodes and so on according to their purpose, are introduced between cathode and plate and modify the flow of electrons by electrostatic attraction or (usually) repulsion. A voltage change on a grid can control a substantially greater change in that between cathode and anode.

    Unlike semiconductors, except perhaps for FETs, the movement of electrons is simply a function of electrostatic field within the active region of the tube, and as a consequence of the very low mass of the electron, the currents can be changed quickly. Moreover, there is no limit to the current density in the space, and the electrodes which do dissapate power are usually metal and can be cooled with forced air, water, or other refrigerants. Today these features cause tubes to be the active device of choice when the signals to be amplified are a power levels of more than about 500 watts.

    The first electronic digital computers used hundreds of vacuum tubes as their active components which, given the reliability of these devices, meant the computers needed frequent repairs to keep them operating. The chief causes of unreliability are the heater used to heat the cathode and the connector into which the tube was plugged.

    Vacuum tube manufacturers in the US are nearly a thing of the past, with the exception of the special purpose types used in broadcast and image sensing and displays. Eimac, GE, RCA, and the like would probably refer to specific types such as "Beam Power Tetrode" and the like, and rarely use the generic terms.

    The cathode ray tube is a special purpose type based on these principles which is used for the visual display in television and computers. X-ray tubes are diodes (two element tubes) used at high voltage; a tungsten anode emits the energetic photons when the energetic electrons hit it. Magnetrons use magnetic fields to constrain the electrons; they provide very simple, high power, ultra-high frequency signals for radar, microwave ovens, and the like. Klystrons amplify signals at high power and microwave frequencies.
Examples
  • They can be used in devices for which vacuum tube valves were unsuitable, such as in hearing aids designed to fit into the ear.
  • vacuum tubes require dc voltage sources as well
  • All glass vacuum tube full glass al-n-al vacuum tube
  • All glass vacuum tube full glass al-n-al vacuum tube
  • Used as frame of vacuum tube, heating elements
  • Lee de forest invents the vacuum tube
  • A specific vacuum tube which converts light into electrical energy
  • Not any air gets into the vacuum tube
  • Slide-back vacuum tube voltmeter
  • The ancestor of these miniature electronic devices is the vacuum tube
  • More examples:  1  2  3  4  5
What is the meaning of vacuum tube and how to define vacuum tube in English? vacuum tube meaning, what does vacuum tube mean in a sentence? vacuum tube meaningvacuum tube definition, translation, pronunciation, synonyms and example sentences are provided by eng.ichacha.net.