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 The needle is then connected to the vacuum and the blood or other fluid withdrawn.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 ?
International competitive bidding, tender is invited by INSTITUTE OF TRANSFUSION MEDICINE for Vacuum tubes, needles and Esmarch~s button tourniquet.
Samsung's Vacuum Tube Soundbar (model HW-F750) resolves consumers' desire for pure power and warm, natural sound by integrating a vacuum tube amplifier into a soundbar for the first time.
Like the Vacuum Tube Soundbar, this product can also be used as a wireless television speaker.
After exhibiting vacuum tube technology at the Carbon Trust conference in December, the companies have received a number of inquiries from potential customers - including the Ministry of Defence.
Typical tube complement for the commercial vacuum tube amplifiers is listed in Table 1.
today announced the availability of new premium products incorporating vacuum tube amplifiers that offer rich, harmonious sound qualities.
Constructed with a copolymer resin, the Rhino Tube vacuum tube for lifters can perform up to 1 million flexes.
Permitting one-handed operation, the JumboFlex 50 vacuum tube lifter allows operators to lift 110-pound loads.
The pivotal contributions of an embryonic microwave power tube capability to Allied success in World War II and the dramatic expansion of military electronics during the Korean conflict led to a veritable explosion in vacuum tube electronics R&D in the 1950s and early 1960s.
Showcases the first multi-device audio dock with vacuum tube technology and the industry's first audio dock with extended multi-device compatibility
Constructed of copolymer resin, the Rhino Tube for vacuum tube lifters is offered as a replacement for neoprene cloth tubes, and provides enhanced resilience and reliability.
Cyto-Chex BCT, a direct-draw vacuum tube for the collection, transport, and retention of whole-blood samples for immunophenotyping by flow cytometry, contains a preservative reagent that maintains the integrity of white blood cells at room temperature three times longer than traditional methods.