| slovo | definícia |
cathode ray
(encz) | cathode ray,elektronový paprsek Zdeněk Brož |
cathode ray
(encz) | cathode ray,paprsek elektronů Zdeněk Brož |
Cathode ray
(gcide) | Cathode \Cath"ode\, n. [Gr. ? descent; ? down + ? way.]
(Physics)
The part of a voltaic battery by which the electric current
leaves substances through which it passes, or the surface at
which the electric current passes out of the electrolyte; the
negative pole; -- opposed to anode. --Faraday.
[1913 Webster]
Cathode ray (Phys.), a kind of ray generated at the cathode
in a vacuum tube, by the electrical discharge.
[1913 Webster] |
cathode ray
(wn) | cathode ray
n 1: a beam of electrons emitted by the cathode of an electrical
discharge tube |
| | podobné slovo | definícia |
Cathode ray
(gcide) | Cathode \Cath"ode\, n. [Gr. ? descent; ? down + ? way.]
(Physics)
The part of a voltaic battery by which the electric current
leaves substances through which it passes, or the surface at
which the electric current passes out of the electrolyte; the
negative pole; -- opposed to anode. --Faraday.
[1913 Webster]
Cathode ray (Phys.), a kind of ray generated at the cathode
in a vacuum tube, by the electrical discharge.
[1913 Webster] |
cathode rays
(gcide) | Electron \E*lec"tron\, n. [NL., fr. Gr. 'h`lektron. See
Electric.]
1. Amber; also, the alloy of gold and silver, called
electrum. [archaic]
[1913 Webster]
2. (Physics & Chem.) one of the fundamental subatomic
particles, having a negative charge and about one
thousandth the mass of a hydrogen atom. The electron
carries (or is) a natural unit of negative electricity,
equal to 3.4 x 10^-10 electrostatic units, and is
classed by physicists as a lepton. Its mass is
practically constant at the lesser speeds, but increases
due to relativistic effects as the velocity approaches
that of light. Electrons are all of one kind, so far as is
known. Thus far, no structure has been detected within an
electron, and it is probably one of the ultimate composite
constituents of all matter. An atom or group of atoms from
which an electron has been detached has a positive charge
and is called a cation. Electrons are projected from the
cathode of vacuum tubes (including television picture
tubes) as cathode rays and from radioactive substances
as the beta rays. Previously also referred to as
corpuscle, an obsolete term. The motion of electrons
through metallic conductors is observed as an electric
current. A particle identical to the electron in mass and
most other respects, but having a positive instead of a
negative charge, is called a positron, or antielectron
[Webster 1913 Suppl. +PJC] Electro-negative |
cathode ray tube
(foldoc) | cathode ray tube
CRT
(CRT) An electrical device for displaying images by
exciting phosphor dots with a scanned electron beam. CRTs are
found in computer VDUs and monitors, televisions and
oscilloscopes. The first commercially practical CRT was
perfected on 29 January 1901 by Allen B DuMont.
A large glass envelope containing a negative electrode (the
cathode) emits electrons (formerly called "cathode rays") when
heated, as in a vacuum tube. The electrons are accelerated
across a large voltage gradient toward the flat surface of
the tube (the screen) which is covered with phosphor. When an
electron strikes the phosphor, light is emitted. The electron
beam is deflected by electromagnetic coils around the outside
of the tube so that it scans across the screen, usually in
horizontal stripes. This scan pattern is known as a raster.
By controlling the current in the beam, the brightness at any
particular point (roughly a "pixel") can be varied.
Different phosphors have different "persistence" - the
length of time for which they glow after being struck by
electrons. If the scanning is done fast enough, the eye sees
a steady image, due to both the persistence of the phospor and
of the eye itself. CRTs also differ in their dot pitch,
which determines their spatial resolution, and in whether
they use interlace or not.
(1994-11-17)
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