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V 1. Abbreviation of VOLT. 2. Symbol (ital) for
VOLTAGE or POTENTIAL. 3. Symbol for VANA-
DIUM. 4. Symbol for VOLUME. 5. Symbol (ital)
for RELUCTIVITY. 6. Abbreviation of VERTICAL.
(Also, vert.)
v 1. Abbreviation of VELOCITY. 2. Abbreviation of
VECTOR.
VA Abbreviation of VOLT-AMPERE.
V/A Abbreviation of volts per ampere (ohms).
VAC Abbreviation of vector analog computer.
vac Abbreviation of VACUUM.
V ac Symbol for AC VOLTS. (Also, Vac.)
vacancy In a crystal lattice, a position not occupied
by a nucleus.
Bonds
Vacancies
Nuclei
vacancy
vacuum A space from which all air and other gases
have been removed to the greatest practicable extent.
Some electronic parts, such as the elements
of an electron tube, are housed in an evacuated
space to protect them from the deterioration that
would result from open-air operation.
vacuum capacitor A plate- or concentric-cylindertype
capacitor sealed in an evacuated glass tube
or bulb. The vacuum acts as the dielectric and
provides a dielectric constant of 1 and very high
voltage breakdown.
vacuum deposition The electrical application of a
layer of one material (such as a metal) to the surface
of another (the substrate), carried out in a
vacuum chamber (e.g., evaporation and sputtering).
Also see DEPOSITION and EVAPORATION,
1.
vacuum envelope The shell or tube of an electron
tube, X-ray tube, or other electron device that requires
a vacuum.
vacuum evaporation A method of manufacturing
thin-film circuits by vaporizing a substance, and
letting it accumulate or condense on a base.
vacuum gauge An instrument for measuring the
vacuum in a device being evacuated. One of the
several varieties of this gauge uses the elements
of a triode, which are sealed in part of the vacuum
system, some characteristic of the tube being
continuously monitored as the vacuum
pumping progresses. Another uses a thermistor
sealed in part of the system; the resistance of the
thermistor changes proportionately during the
vacuum pumping.
vacuum impregnation The impregnation of a device
(such as a capacitor, transformer, or choke
coil) in a vacuum chamber. The process causes
the pores in the device and its insulating materials
to be completely filled with the impregnant.
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