| slovo | definícia |
vacuum
(mass) | vacuum
- vákuum, vysávač, vysávať |
vacuum
(encz) | vacuum,luxovat v: Michal Ambrož |
vacuum
(encz) | vacuum,podtlak n: saša |
vacuum
(encz) | vacuum,podtlakový adj: Michal Ambrož |
vacuum
(encz) | vacuum,vakuovaný adj: web |
vacuum
(encz) | vacuum,vakuový adj: web |
vacuum
(encz) | vacuum,vakuum n: saša |
vacuum
(encz) | vacuum,vyluxovat v: Michal Ambrož |
vacuum
(encz) | vacuum,vysát Zdeněk Brož |
vacuum
(encz) | vacuum,vysávat v: Michal Ambrož |
vacuum
(encz) | vacuum,vzduchoprázdno n: web |
vacuum
(encz) | vacuum,vzduchoprázdný adj: web |
Vacuum
(gcide) | Vacuum \Vac"u*um\ (v[a^]k"[-u]*[u^]m), n.; pl. E. Vacuums
(v[a^]k"[-u]*[u^]mz), L. Vacua (v[a^]k"[-u]*[.a]). [L., fr.
vacuus empty. See Vacuous.]
1. (Physics) A space entirely devoid of matter (called also,
by way of distinction, absolute vacuum); hence, in a more
general sense, a space, as the interior of a closed
vessel, which has been exhausted to a high or the highest
degree by an air pump or other artificial means; as, water
boils at a reduced temperature in a vacuum.
[1913 Webster]
[1913 Webster]
2. The condition of rarefaction, or reduction of pressure
below that of the atmosphere, in a vessel, as the
condenser of a steam engine, which is nearly exhausted of
air or steam, etc.; as, a vacuum of 26 inches of mercury,
or 13 pounds per square inch.
[1913 Webster]
Vacuum brake, a kind of continuous brake operated by
exhausting the air from some appliance under each car, and
so causing the pressure of the atmosphere to apply the
brakes.
Vacuum pan (Technol.), a kind of large closed metallic
retort used in sugar making for boiling down sirup. It is
so connected with an exhausting apparatus that a partial
vacuum is formed within. This allows the evaporation and
concentration to take place at a lower atmospheric
pressure and hence also at a lower temperature, which
largely obviates the danger of burning the sugar, and
shortens the process.
Vacuum pump. Same as Pulsometer, 1.
Vacuum tube (Phys.),
(a) a glass tube provided with platinum electrodes and
exhausted, for the passage of the electrical
discharge; a Geissler tube.
(a) any tube used in electronic devices, containing a
vacuum and used to control the flow of electrons in a
circuit, as a vacuum diode, triode, tetrode, or
pentode.
Vacuum valve, a safety valve opening inward to admit air to
a vessel in which the pressure is less than that of the
atmosphere, in order to prevent collapse.
Torricellian vacuum. See under Torricellian.
[1913 Webster] |
vacuum
(gcide) | Vacuum cleaner \Vac"u*um clean"er\
A machine for cleaning carpets, tapestry, upholstered work,
etc., by suction; -- sometimes called a vacuum.
[Webster 1913 Suppl.] |
vacuum
(wn) | vacuum
n 1: the absence of matter [syn: vacuum, vacuity]
2: an empty area or space; "the huge desert voids"; "the
emptiness of outer space"; "without their support he'll be
ruling in a vacuum" [syn: void, vacancy, emptiness,
vacuum]
3: a region that is devoid of matter [syn: vacuum, vacuity]
4: an electrical home appliance that cleans by suction [syn:
vacuum, vacuum cleaner]
v 1: clean with a vacuum cleaner; "vacuum the carpets" [syn:
vacuum, vacuum-clean, hoover] |
| | podobné slovo | definícia |
moist seedlings pickling in mild vacuum
(encz) | moist seedlings pickling in mild vacuum,mokré moření sadby ve slabém
vakuu [eko.] RNDr. Pavel Piskač |
moist sowing seed pickling in mild vacuum
(encz) | moist sowing seed pickling in mild vacuum,mokré moření osiva ve slabém
vakuu [eko.] RNDr. Pavel Piskač |
thermionic vacuum tube
(encz) | thermionic vacuum tube, n: |
uhv (ultra high vacuum)
(encz) | UHV (ultra high vacuum),ultra-vysoké vakuum n: [chem.] [fyz.] web |
ultra high vacuum
(encz) | ultra high vacuum,ultravysoké vakuum n: [chem.] [fyz.] web |
vacuum aspiration
(encz) | vacuum aspiration, n: |
vacuum bag
(encz) | vacuum bag, n: |
vacuum bomb
(encz) | vacuum bomb,vakuová bomba n: bomba využívající palivo-vzdušné trhaviny
působí silnou tlakovou vlnou, která vytěsní kyslík z prostoru a udusí
vše živé v prostoru exploze BartyCok |
vacuum bottle
(encz) | vacuum bottle,termoska BartyCok |
vacuum chamber
(encz) | vacuum chamber,podtlaková komora n: BartyCok |
vacuum cleaner
(encz) | vacuum cleaner,vysavač |
vacuum flask
(encz) | vacuum flask,termoska n: láhev s dvojitou stěnou vyplněnou
vakuem BartyCok |
vacuum gage
(encz) | vacuum gage,vakuometr n: BartyCok |
vacuum gauge
(encz) | vacuum gauge,vakuometr n: web |
vacuum pump
(encz) | vacuum pump,sací pumpa n: webvacuum pump,vakuová pumpa n: Vašek Stodůlkavacuum pump,vývěva n: [fyz.] Martin Marble Beránek |
vacuum tube
(encz) | vacuum tube,elektronka fjeyvacuum tube,výbojka fjey |
vacuum-clean
(encz) | vacuum-clean,vysávat vysavačem v: web |
vacuum-packed
(encz) | vacuum-packed,vakuově baleno luke |
vacuumed
(encz) | vacuumed,evakuováno saša |
vacuuming
(encz) | vacuuming,vysávání n: Zdeněk Brož |
vacuums
(encz) | vacuums,vysavače Zdeněk Brož |
Torricellian vacuum
(gcide) | Torricellian \Tor`ri*cel"li*an\, a.
Of or pertaining to Torricelli, an Italian philosopher and
mathematician, who, in 1643, discovered that the rise of a
liquid in a tube, as in the barometer, is due to atmospheric
pressure. See Barometer.
[1913 Webster]
Torricellian tube, a glass tube thirty or more inches in
length, open at the lower end and hermetically sealed at
the upper, such as is used in the barometer.
Torricellian vacuum (Physics), a vacuum produced by filling
with a fluid, as mercury, a tube hermetically closed at
one end, and, after immersing the other end in a vessel of
the same fluid, allowing the inclosed fluid to descend
till it is counterbalanced by the pressure of the
atmosphere, as in the barometer. --Hutton.
[1913 Webster]Vacuum \Vac"u*um\ (v[a^]k"[-u]*[u^]m), n.; pl. E. Vacuums
(v[a^]k"[-u]*[u^]mz), L. Vacua (v[a^]k"[-u]*[.a]). [L., fr.
vacuus empty. See Vacuous.]
1. (Physics) A space entirely devoid of matter (called also,
by way of distinction, absolute vacuum); hence, in a more
general sense, a space, as the interior of a closed
vessel, which has been exhausted to a high or the highest
degree by an air pump or other artificial means; as, water
boils at a reduced temperature in a vacuum.
[1913 Webster]
[1913 Webster]
2. The condition of rarefaction, or reduction of pressure
below that of the atmosphere, in a vessel, as the
condenser of a steam engine, which is nearly exhausted of
air or steam, etc.; as, a vacuum of 26 inches of mercury,
or 13 pounds per square inch.
[1913 Webster]
Vacuum brake, a kind of continuous brake operated by
exhausting the air from some appliance under each car, and
so causing the pressure of the atmosphere to apply the
brakes.
Vacuum pan (Technol.), a kind of large closed metallic
retort used in sugar making for boiling down sirup. It is
so connected with an exhausting apparatus that a partial
vacuum is formed within. This allows the evaporation and
concentration to take place at a lower atmospheric
pressure and hence also at a lower temperature, which
largely obviates the danger of burning the sugar, and
shortens the process.
Vacuum pump. Same as Pulsometer, 1.
Vacuum tube (Phys.),
(a) a glass tube provided with platinum electrodes and
exhausted, for the passage of the electrical
discharge; a Geissler tube.
(a) any tube used in electronic devices, containing a
vacuum and used to control the flow of electrons in a
circuit, as a vacuum diode, triode, tetrode, or
pentode.
Vacuum valve, a safety valve opening inward to admit air to
a vessel in which the pressure is less than that of the
atmosphere, in order to prevent collapse.
Torricellian vacuum. See under Torricellian.
[1913 Webster] |
Vacuum
(gcide) | Vacuum \Vac"u*um\ (v[a^]k"[-u]*[u^]m), n.; pl. E. Vacuums
(v[a^]k"[-u]*[u^]mz), L. Vacua (v[a^]k"[-u]*[.a]). [L., fr.
vacuus empty. See Vacuous.]
1. (Physics) A space entirely devoid of matter (called also,
by way of distinction, absolute vacuum); hence, in a more
general sense, a space, as the interior of a closed
vessel, which has been exhausted to a high or the highest
degree by an air pump or other artificial means; as, water
boils at a reduced temperature in a vacuum.
[1913 Webster]
[1913 Webster]
2. The condition of rarefaction, or reduction of pressure
below that of the atmosphere, in a vessel, as the
condenser of a steam engine, which is nearly exhausted of
air or steam, etc.; as, a vacuum of 26 inches of mercury,
or 13 pounds per square inch.
[1913 Webster]
Vacuum brake, a kind of continuous brake operated by
exhausting the air from some appliance under each car, and
so causing the pressure of the atmosphere to apply the
brakes.
Vacuum pan (Technol.), a kind of large closed metallic
retort used in sugar making for boiling down sirup. It is
so connected with an exhausting apparatus that a partial
vacuum is formed within. This allows the evaporation and
concentration to take place at a lower atmospheric
pressure and hence also at a lower temperature, which
largely obviates the danger of burning the sugar, and
shortens the process.
Vacuum pump. Same as Pulsometer, 1.
Vacuum tube (Phys.),
(a) a glass tube provided with platinum electrodes and
exhausted, for the passage of the electrical
discharge; a Geissler tube.
(a) any tube used in electronic devices, containing a
vacuum and used to control the flow of electrons in a
circuit, as a vacuum diode, triode, tetrode, or
pentode.
Vacuum valve, a safety valve opening inward to admit air to
a vessel in which the pressure is less than that of the
atmosphere, in order to prevent collapse.
Torricellian vacuum. See under Torricellian.
[1913 Webster]Vacuum cleaner \Vac"u*um clean"er\
A machine for cleaning carpets, tapestry, upholstered work,
etc., by suction; -- sometimes called a vacuum.
[Webster 1913 Suppl.] |
Vacuum brake
(gcide) | Vacuum \Vac"u*um\ (v[a^]k"[-u]*[u^]m), n.; pl. E. Vacuums
(v[a^]k"[-u]*[u^]mz), L. Vacua (v[a^]k"[-u]*[.a]). [L., fr.
vacuus empty. See Vacuous.]
1. (Physics) A space entirely devoid of matter (called also,
by way of distinction, absolute vacuum); hence, in a more
general sense, a space, as the interior of a closed
vessel, which has been exhausted to a high or the highest
degree by an air pump or other artificial means; as, water
boils at a reduced temperature in a vacuum.
[1913 Webster]
[1913 Webster]
2. The condition of rarefaction, or reduction of pressure
below that of the atmosphere, in a vessel, as the
condenser of a steam engine, which is nearly exhausted of
air or steam, etc.; as, a vacuum of 26 inches of mercury,
or 13 pounds per square inch.
[1913 Webster]
Vacuum brake, a kind of continuous brake operated by
exhausting the air from some appliance under each car, and
so causing the pressure of the atmosphere to apply the
brakes.
Vacuum pan (Technol.), a kind of large closed metallic
retort used in sugar making for boiling down sirup. It is
so connected with an exhausting apparatus that a partial
vacuum is formed within. This allows the evaporation and
concentration to take place at a lower atmospheric
pressure and hence also at a lower temperature, which
largely obviates the danger of burning the sugar, and
shortens the process.
Vacuum pump. Same as Pulsometer, 1.
Vacuum tube (Phys.),
(a) a glass tube provided with platinum electrodes and
exhausted, for the passage of the electrical
discharge; a Geissler tube.
(a) any tube used in electronic devices, containing a
vacuum and used to control the flow of electrons in a
circuit, as a vacuum diode, triode, tetrode, or
pentode.
Vacuum valve, a safety valve opening inward to admit air to
a vessel in which the pressure is less than that of the
atmosphere, in order to prevent collapse.
Torricellian vacuum. See under Torricellian.
[1913 Webster] |
Vacuum cleaner
(gcide) | Vacuum cleaner \Vac"u*um clean"er\
A machine for cleaning carpets, tapestry, upholstered work,
etc., by suction; -- sometimes called a vacuum.
[Webster 1913 Suppl.]Appliance \Ap*pli"ance\, n.
1. The act of applying; application.
[1913 Webster]
2. subservience; compliance. [Obs.] --Shak.
[1913 Webster]
3. A thing applied or used as a means to an end; an apparatus
or device; as, to use various appliances; a mechanical
appliance; a machine with its appliances.
[1913 Webster]
4. Specifically: An apparatus or device, usually powered
electrically, used in homes to perform domestic functions.
An appliance is often categorized as a major appliance or
a minor appliance by its cost. Common major appliances are
the refrigerator, washing machine, clothes drier,
oven, and dishwasher. Some minor appliances are a
toaster, vacuum cleaner or microwave oven.
[PJC] |
vacuum cleaner
(gcide) | Vacuum cleaner \Vac"u*um clean"er\
A machine for cleaning carpets, tapestry, upholstered work,
etc., by suction; -- sometimes called a vacuum.
[Webster 1913 Suppl.]Appliance \Ap*pli"ance\, n.
1. The act of applying; application.
[1913 Webster]
2. subservience; compliance. [Obs.] --Shak.
[1913 Webster]
3. A thing applied or used as a means to an end; an apparatus
or device; as, to use various appliances; a mechanical
appliance; a machine with its appliances.
[1913 Webster]
4. Specifically: An apparatus or device, usually powered
electrically, used in homes to perform domestic functions.
An appliance is often categorized as a major appliance or
a minor appliance by its cost. Common major appliances are
the refrigerator, washing machine, clothes drier,
oven, and dishwasher. Some minor appliances are a
toaster, vacuum cleaner or microwave oven.
[PJC] |
Vacuum gauge
(gcide) | Gauge \Gauge\, n. [Written also gage.]
1. A measure; a standard of measure; an instrument to
determine dimensions, distance, or capacity; a standard.
[1913 Webster]
This plate must be a gauge to file your worm and
groove to equal breadth by. --Moxon.
[1913 Webster]
There is not in our hands any fixed gauge of minds.
--I. Taylor.
[1913 Webster]
2. Measure; dimensions; estimate.
[1913 Webster]
The gauge and dimensions of misery, depression, and
contempt. --Burke.
[1913 Webster]
3. (Mach. & Manuf.) Any instrument for ascertaining or
regulating the dimensions or forms of things; a templet or
template; as, a button maker's gauge.
[1913 Webster]
4. (Physics) Any instrument or apparatus for measuring the
state of a phenomenon, or for ascertaining its numerical
elements at any moment; -- usually applied to some
particular instrument; as, a rain gauge; a steam gauge.
[1913 Webster]
5. (Naut.)
(a) Relative positions of two or more vessels with
reference to the wind; as, a vessel has the weather
gauge of another when on the windward side of it, and
the lee gauge when on the lee side of it.
(b) The depth to which a vessel sinks in the water.
--Totten.
[1913 Webster]
6. The distance between the rails of a railway.
[1913 Webster]
Note: The standard gauge of railroads in most countries is
four feet, eight and one half inches. Wide, or broad,
gauge, in the United States, is six feet; in England,
seven feet, and generally any gauge exceeding standard
gauge. Any gauge less than standard gauge is now called
narrow gauge. It varies from two feet to three feet six
inches.
[1913 Webster]
7. (Plastering) The quantity of plaster of Paris used with
common plaster to accelerate its setting.
[1913 Webster]
8. (Building) That part of a shingle, slate, or tile, which
is exposed to the weather, when laid; also, one course of
such shingles, slates, or tiles.
[1913 Webster]
Gauge of a carriage, car, etc., the distance between the
wheels; -- ordinarily called the track.
Gauge cock, a stop cock used as a try cock for ascertaining
the height of the water level in a steam boiler.
Gauge concussion (Railroads), the jar caused by a car-wheel
flange striking the edge of the rail.
Gauge glass, a glass tube for a water gauge.
Gauge lathe, an automatic lathe for turning a round object
having an irregular profile, as a baluster or chair round,
to a templet or gauge.
Gauge point, the diameter of a cylinder whose altitude is
one inch, and contents equal to that of a unit of a given
measure; -- a term used in gauging casks, etc.
Gauge rod, a graduated rod, for measuring the capacity of
barrels, casks, etc.
Gauge saw, a handsaw, with a gauge to regulate the depth of
cut. --Knight.
Gauge stuff, a stiff and compact plaster, used in making
cornices, moldings, etc., by means of a templet.
Gauge wheel, a wheel at the forward end of a plow beam, to
determine the depth of the furrow.
Joiner's gauge, an instrument used to strike a line
parallel to the straight side of a board, etc.
Printer's gauge, an instrument to regulate the length of
the page.
Rain gauge, an instrument for measuring the quantity of
rain at any given place.
Salt gauge, or Brine gauge, an instrument or contrivance
for indicating the degree of saltness of water from its
specific gravity, as in the boilers of ocean steamers.
Sea gauge, an instrument for finding the depth of the sea.
Siphon gauge, a glass siphon tube, partly filled with
mercury, -- used to indicate pressure, as of steam, or the
degree of rarefaction produced in the receiver of an air
pump or other vacuum; a manometer.
Sliding gauge. (Mach.)
(a) A templet or pattern for gauging the commonly accepted
dimensions or shape of certain parts in general use,
as screws, railway-car axles, etc.
(b) A gauge used only for testing other similar gauges,
and preserved as a reference, to detect wear of the
working gauges.
(c) (Railroads) See Note under Gauge, n., 5.
Star gauge (Ordnance), an instrument for measuring the
diameter of the bore of a cannon at any point of its
length.
Steam gauge, an instrument for measuring the pressure of
steam, as in a boiler.
Tide gauge, an instrument for determining the height of the
tides.
Vacuum gauge, a species of barometer for determining the
relative elasticities of the vapor in the condenser of a
steam engine and the air.
Water gauge.
(a) A contrivance for indicating the height of a water
surface, as in a steam boiler; as by a gauge cock or
glass.
(b) The height of the water in the boiler.
Wind gauge, an instrument for measuring the force of the
wind on any given surface; an anemometer.
Wire gauge, a gauge for determining the diameter of wire or
the thickness of sheet metal; also, a standard of size.
See under Wire.
[1913 Webster] |
Vacuum pan
(gcide) | Vacuum \Vac"u*um\ (v[a^]k"[-u]*[u^]m), n.; pl. E. Vacuums
(v[a^]k"[-u]*[u^]mz), L. Vacua (v[a^]k"[-u]*[.a]). [L., fr.
vacuus empty. See Vacuous.]
1. (Physics) A space entirely devoid of matter (called also,
by way of distinction, absolute vacuum); hence, in a more
general sense, a space, as the interior of a closed
vessel, which has been exhausted to a high or the highest
degree by an air pump or other artificial means; as, water
boils at a reduced temperature in a vacuum.
[1913 Webster]
[1913 Webster]
2. The condition of rarefaction, or reduction of pressure
below that of the atmosphere, in a vessel, as the
condenser of a steam engine, which is nearly exhausted of
air or steam, etc.; as, a vacuum of 26 inches of mercury,
or 13 pounds per square inch.
[1913 Webster]
Vacuum brake, a kind of continuous brake operated by
exhausting the air from some appliance under each car, and
so causing the pressure of the atmosphere to apply the
brakes.
Vacuum pan (Technol.), a kind of large closed metallic
retort used in sugar making for boiling down sirup. It is
so connected with an exhausting apparatus that a partial
vacuum is formed within. This allows the evaporation and
concentration to take place at a lower atmospheric
pressure and hence also at a lower temperature, which
largely obviates the danger of burning the sugar, and
shortens the process.
Vacuum pump. Same as Pulsometer, 1.
Vacuum tube (Phys.),
(a) a glass tube provided with platinum electrodes and
exhausted, for the passage of the electrical
discharge; a Geissler tube.
(a) any tube used in electronic devices, containing a
vacuum and used to control the flow of electrons in a
circuit, as a vacuum diode, triode, tetrode, or
pentode.
Vacuum valve, a safety valve opening inward to admit air to
a vessel in which the pressure is less than that of the
atmosphere, in order to prevent collapse.
Torricellian vacuum. See under Torricellian.
[1913 Webster] |
vacuum pump
(gcide) | Pulsometer \Pul*som"e*ter\, n. [Pulse + -meter.]
[1913 Webster]
1. A device, with valves, for raising water by steam, partly
by atmospheric pressure, and partly by the direct action
of the steam on the water, without the intervention of a
piston; -- also called vacuum pump.
[1913 Webster]
2. A pulsimeter.
[1913 Webster]Vacuum \Vac"u*um\ (v[a^]k"[-u]*[u^]m), n.; pl. E. Vacuums
(v[a^]k"[-u]*[u^]mz), L. Vacua (v[a^]k"[-u]*[.a]). [L., fr.
vacuus empty. See Vacuous.]
1. (Physics) A space entirely devoid of matter (called also,
by way of distinction, absolute vacuum); hence, in a more
general sense, a space, as the interior of a closed
vessel, which has been exhausted to a high or the highest
degree by an air pump or other artificial means; as, water
boils at a reduced temperature in a vacuum.
[1913 Webster]
[1913 Webster]
2. The condition of rarefaction, or reduction of pressure
below that of the atmosphere, in a vessel, as the
condenser of a steam engine, which is nearly exhausted of
air or steam, etc.; as, a vacuum of 26 inches of mercury,
or 13 pounds per square inch.
[1913 Webster]
Vacuum brake, a kind of continuous brake operated by
exhausting the air from some appliance under each car, and
so causing the pressure of the atmosphere to apply the
brakes.
Vacuum pan (Technol.), a kind of large closed metallic
retort used in sugar making for boiling down sirup. It is
so connected with an exhausting apparatus that a partial
vacuum is formed within. This allows the evaporation and
concentration to take place at a lower atmospheric
pressure and hence also at a lower temperature, which
largely obviates the danger of burning the sugar, and
shortens the process.
Vacuum pump. Same as Pulsometer, 1.
Vacuum tube (Phys.),
(a) a glass tube provided with platinum electrodes and
exhausted, for the passage of the electrical
discharge; a Geissler tube.
(a) any tube used in electronic devices, containing a
vacuum and used to control the flow of electrons in a
circuit, as a vacuum diode, triode, tetrode, or
pentode.
Vacuum valve, a safety valve opening inward to admit air to
a vessel in which the pressure is less than that of the
atmosphere, in order to prevent collapse.
Torricellian vacuum. See under Torricellian.
[1913 Webster] |
Vacuum pump
(gcide) | Pulsometer \Pul*som"e*ter\, n. [Pulse + -meter.]
[1913 Webster]
1. A device, with valves, for raising water by steam, partly
by atmospheric pressure, and partly by the direct action
of the steam on the water, without the intervention of a
piston; -- also called vacuum pump.
[1913 Webster]
2. A pulsimeter.
[1913 Webster]Vacuum \Vac"u*um\ (v[a^]k"[-u]*[u^]m), n.; pl. E. Vacuums
(v[a^]k"[-u]*[u^]mz), L. Vacua (v[a^]k"[-u]*[.a]). [L., fr.
vacuus empty. See Vacuous.]
1. (Physics) A space entirely devoid of matter (called also,
by way of distinction, absolute vacuum); hence, in a more
general sense, a space, as the interior of a closed
vessel, which has been exhausted to a high or the highest
degree by an air pump or other artificial means; as, water
boils at a reduced temperature in a vacuum.
[1913 Webster]
[1913 Webster]
2. The condition of rarefaction, or reduction of pressure
below that of the atmosphere, in a vessel, as the
condenser of a steam engine, which is nearly exhausted of
air or steam, etc.; as, a vacuum of 26 inches of mercury,
or 13 pounds per square inch.
[1913 Webster]
Vacuum brake, a kind of continuous brake operated by
exhausting the air from some appliance under each car, and
so causing the pressure of the atmosphere to apply the
brakes.
Vacuum pan (Technol.), a kind of large closed metallic
retort used in sugar making for boiling down sirup. It is
so connected with an exhausting apparatus that a partial
vacuum is formed within. This allows the evaporation and
concentration to take place at a lower atmospheric
pressure and hence also at a lower temperature, which
largely obviates the danger of burning the sugar, and
shortens the process.
Vacuum pump. Same as Pulsometer, 1.
Vacuum tube (Phys.),
(a) a glass tube provided with platinum electrodes and
exhausted, for the passage of the electrical
discharge; a Geissler tube.
(a) any tube used in electronic devices, containing a
vacuum and used to control the flow of electrons in a
circuit, as a vacuum diode, triode, tetrode, or
pentode.
Vacuum valve, a safety valve opening inward to admit air to
a vessel in which the pressure is less than that of the
atmosphere, in order to prevent collapse.
Torricellian vacuum. See under Torricellian.
[1913 Webster] |
Vacuum tube
(gcide) | Vacuum \Vac"u*um\ (v[a^]k"[-u]*[u^]m), n.; pl. E. Vacuums
(v[a^]k"[-u]*[u^]mz), L. Vacua (v[a^]k"[-u]*[.a]). [L., fr.
vacuus empty. See Vacuous.]
1. (Physics) A space entirely devoid of matter (called also,
by way of distinction, absolute vacuum); hence, in a more
general sense, a space, as the interior of a closed
vessel, which has been exhausted to a high or the highest
degree by an air pump or other artificial means; as, water
boils at a reduced temperature in a vacuum.
[1913 Webster]
[1913 Webster]
2. The condition of rarefaction, or reduction of pressure
below that of the atmosphere, in a vessel, as the
condenser of a steam engine, which is nearly exhausted of
air or steam, etc.; as, a vacuum of 26 inches of mercury,
or 13 pounds per square inch.
[1913 Webster]
Vacuum brake, a kind of continuous brake operated by
exhausting the air from some appliance under each car, and
so causing the pressure of the atmosphere to apply the
brakes.
Vacuum pan (Technol.), a kind of large closed metallic
retort used in sugar making for boiling down sirup. It is
so connected with an exhausting apparatus that a partial
vacuum is formed within. This allows the evaporation and
concentration to take place at a lower atmospheric
pressure and hence also at a lower temperature, which
largely obviates the danger of burning the sugar, and
shortens the process.
Vacuum pump. Same as Pulsometer, 1.
Vacuum tube (Phys.),
(a) a glass tube provided with platinum electrodes and
exhausted, for the passage of the electrical
discharge; a Geissler tube.
(a) any tube used in electronic devices, containing a
vacuum and used to control the flow of electrons in a
circuit, as a vacuum diode, triode, tetrode, or
pentode.
Vacuum valve, a safety valve opening inward to admit air to
a vessel in which the pressure is less than that of the
atmosphere, in order to prevent collapse.
Torricellian vacuum. See under Torricellian.
[1913 Webster] |
Vacuum valve
(gcide) | Vacuum \Vac"u*um\ (v[a^]k"[-u]*[u^]m), n.; pl. E. Vacuums
(v[a^]k"[-u]*[u^]mz), L. Vacua (v[a^]k"[-u]*[.a]). [L., fr.
vacuus empty. See Vacuous.]
1. (Physics) A space entirely devoid of matter (called also,
by way of distinction, absolute vacuum); hence, in a more
general sense, a space, as the interior of a closed
vessel, which has been exhausted to a high or the highest
degree by an air pump or other artificial means; as, water
boils at a reduced temperature in a vacuum.
[1913 Webster]
[1913 Webster]
2. The condition of rarefaction, or reduction of pressure
below that of the atmosphere, in a vessel, as the
condenser of a steam engine, which is nearly exhausted of
air or steam, etc.; as, a vacuum of 26 inches of mercury,
or 13 pounds per square inch.
[1913 Webster]
Vacuum brake, a kind of continuous brake operated by
exhausting the air from some appliance under each car, and
so causing the pressure of the atmosphere to apply the
brakes.
Vacuum pan (Technol.), a kind of large closed metallic
retort used in sugar making for boiling down sirup. It is
so connected with an exhausting apparatus that a partial
vacuum is formed within. This allows the evaporation and
concentration to take place at a lower atmospheric
pressure and hence also at a lower temperature, which
largely obviates the danger of burning the sugar, and
shortens the process.
Vacuum pump. Same as Pulsometer, 1.
Vacuum tube (Phys.),
(a) a glass tube provided with platinum electrodes and
exhausted, for the passage of the electrical
discharge; a Geissler tube.
(a) any tube used in electronic devices, containing a
vacuum and used to control the flow of electrons in a
circuit, as a vacuum diode, triode, tetrode, or
pentode.
Vacuum valve, a safety valve opening inward to admit air to
a vessel in which the pressure is less than that of the
atmosphere, in order to prevent collapse.
Torricellian vacuum. See under Torricellian.
[1913 Webster] |
Vacuums
(gcide) | Vacuum \Vac"u*um\ (v[a^]k"[-u]*[u^]m), n.; pl. E. Vacuums
(v[a^]k"[-u]*[u^]mz), L. Vacua (v[a^]k"[-u]*[.a]). [L., fr.
vacuus empty. See Vacuous.]
1. (Physics) A space entirely devoid of matter (called also,
by way of distinction, absolute vacuum); hence, in a more
general sense, a space, as the interior of a closed
vessel, which has been exhausted to a high or the highest
degree by an air pump or other artificial means; as, water
boils at a reduced temperature in a vacuum.
[1913 Webster]
[1913 Webster]
2. The condition of rarefaction, or reduction of pressure
below that of the atmosphere, in a vessel, as the
condenser of a steam engine, which is nearly exhausted of
air or steam, etc.; as, a vacuum of 26 inches of mercury,
or 13 pounds per square inch.
[1913 Webster]
Vacuum brake, a kind of continuous brake operated by
exhausting the air from some appliance under each car, and
so causing the pressure of the atmosphere to apply the
brakes.
Vacuum pan (Technol.), a kind of large closed metallic
retort used in sugar making for boiling down sirup. It is
so connected with an exhausting apparatus that a partial
vacuum is formed within. This allows the evaporation and
concentration to take place at a lower atmospheric
pressure and hence also at a lower temperature, which
largely obviates the danger of burning the sugar, and
shortens the process.
Vacuum pump. Same as Pulsometer, 1.
Vacuum tube (Phys.),
(a) a glass tube provided with platinum electrodes and
exhausted, for the passage of the electrical
discharge; a Geissler tube.
(a) any tube used in electronic devices, containing a
vacuum and used to control the flow of electrons in a
circuit, as a vacuum diode, triode, tetrode, or
pentode.
Vacuum valve, a safety valve opening inward to admit air to
a vessel in which the pressure is less than that of the
atmosphere, in order to prevent collapse.
Torricellian vacuum. See under Torricellian.
[1913 Webster] |
thermionic vacuum tube
(wn) | thermionic vacuum tube
n 1: electronic device consisting of a system of electrodes
arranged in an evacuated glass or metal envelope [syn:
tube, vacuum tube, thermionic vacuum tube,
thermionic tube, electron tube, thermionic valve] |
vacuum aspiration
(wn) | vacuum aspiration
n 1: a method of induced abortion; prior to the 14th week of
gestation the embryo and placenta are removed by applying
suction to the dilated cervix [syn: suction curettage,
vacuum aspiration] |
vacuum bag
(wn) | vacuum bag
n 1: a bag into which dirt is sucked by a vacuum cleaner [syn:
dust bag, vacuum bag] |
vacuum bomb
(wn) | vacuum bomb
n 1: a bomb that uses a fuel-air explosive; "a thermobaric bomb
can create overpressures equal to an atomic bomb" [syn:
thermobaric bomb, fuel-air bomb, vacuum bomb,
volume-detonation bomb, aerosol bomb] |
vacuum bottle
(wn) | vacuum bottle
n 1: flask with double walls separated by vacuum; used to
maintain substances at high or low temperatures [syn:
vacuum flask, vacuum bottle] |
vacuum chamber
(wn) | vacuum chamber
n 1: a chamber from which nearly all matter (especially air) has
been removed |
vacuum cleaner
(wn) | vacuum cleaner
n 1: an electrical home appliance that cleans by suction [syn:
vacuum, vacuum cleaner] |
vacuum flask
(wn) | vacuum flask
n 1: flask with double walls separated by vacuum; used to
maintain substances at high or low temperatures [syn:
vacuum flask, vacuum bottle] |
vacuum gage
(wn) | vacuum gage
n 1: a gauge for indicating negative atmospheric pressure [syn:
vacuum gauge, vacuum gage] |
vacuum gauge
(wn) | vacuum gauge
n 1: a gauge for indicating negative atmospheric pressure [syn:
vacuum gauge, vacuum gage] |
vacuum pump
(wn) | vacuum pump
n 1: a pump that moves air in or out of something [syn: {air
pump}, vacuum pump] |
vacuum tube
(wn) | vacuum tube
n 1: electronic device consisting of a system of electrodes
arranged in an evacuated glass or metal envelope [syn:
tube, vacuum tube, thermionic vacuum tube,
thermionic tube, electron tube, thermionic valve] |
vacuum-clean
(wn) | vacuum-clean
v 1: clean with a vacuum cleaner; "vacuum the carpets" [syn:
vacuum, vacuum-clean, hoover] |
vacuum tube
(foldoc) | electron tube
firebottle
vacuum tube
(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.
(1996-02-05)
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