vacuum tube

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vac·uum tube

a glass tube from which the air has been removed, containing two or more electrodes, between which passes an electrical current or spark; used in the production of x-rays, or to control circuits. Previously in wide use, the vacuum tube has been supplanted by transistors in electronic circuits.

vacuum tube

A vessel of insulating material (usually glass) that is sealed and has a vacuum sufficiently high to permit the free flow of electrons between the electrodes that extend into the tube from the outside. In England, it is called a vacuum valve.


a space devoid of air or other gas.

vacuum collection
use of a handheld vacuum to recover ectoparasites from the coat of animals.
freed of moisture while in a vacuum. Used in the packaging of food.
vacuum gauge
pressure gauge in a milking machine which indicates the level of vacuum in the system.
vacuum pack
meat or other perishable food is packed in a tightly sealed bag made of copolymers with polyvinyldene chloride and a low vacuum created. A bag made of nylon-polythene laminate is used for bags that are heat-sealed and a high vacuum created. The pack is then frozen for storage or shipment.
vacuum pressure
used as the basis of the modern milking machine; the negative pressure is generated by a vacuum pump and transmitted through metal and rubber pipes to the teat cups and thence to the teats; the continuous basic pressure is what keeps the teat cups on the teats; the periodic fluctuations is what causes the squeezing of the teat walls and the expulsion of the milk from the teats.
vacuum therapy
see cupping.
vacuum tube
many clinical pathology specimens are now collected in evacuated test tubes. A needle connected to the tube through a rubber stopper is passed into a vein. The needle is then connected to the vacuum and the blood or other fluid withdrawn.
References in periodicals archive ?
This flagship HTS incorporates Samsung's proprietary vacuum tube and digital amplifier, as well as the latest in Smart TV features to create the best entertainment experience available.
Thermomax vacuum tube collectors are specifically tailored for Northern European climates and deliver an unrivalled transfer of solar energy into heat, providing up to 70 per cent of hot water requirements throughout the year.
The Welsh Assembly Government helped linked the two companies, which have now secured one of their first contracts to supply and install Thermomax vacuum tubes at the offices of Environment Agency Wales in Cardiff and Bangor.
New in 2012, Samsung's patented vacuum tube amplifier technology allows audio enthusiasts to enjoy music the way it was meant to be heard.
June 19, 2014 /PRNewswire-iReach/ -- The BT-6 is a vacuum tube amplifier hand crafted in a walnut/cherry hardwood enclosure is reminiscent of craftsmanship from 60 years ago.
Samsung's Audio Dock with Vacuum Tube Amplifier - the world's first docking system that incorporates Samsung's proprietary hybrid vacuum tube amplifier technology and supports a broad range of Galaxy S and Apple devices via both docked and wireless connectivity (model DA-E750).
1 Channel Blu-ray 3D Home Theater System - the first home theater system that features Samsung's proprietary vacuum tube amplifier technology that combines both vacuum tubes and a digital amplifier into one unit to create a powerful entertainment experience (model HT-E6730W).
MISSISSAUGA, ON, March 28, 2012 /PRNewswire/ - Samsung Electronics today announced the availability of new premium products incorporating vacuum tube amplifiers that offer rich, harmonious sound qualities.
The upper limit on a computer's speed would apply whether the technology involves vacuum tubes, transistors, electrons, quarks and gluons, or something even more exotic, Lloyd remarks.
The small, simple and tough transistor replaced fragile, bulky and heat-generating vacuum tubes, which had been the heart of electronics for decades.
Instead of the huge, bell-shaped vacuum tubes required by today's devices, Candescent says it has created microscopic cathodes that can work inside a 1-millimeter gap between two pieces of glass.
As part of the Excyte ESR product line, the Excyte 20 also offers positive patient identification through all stages of testing utilizing the patented Excyte Slider technology and direct draw vacuum tubes that increases safety by limiting exposure to blood.