Page 32 - The Illustrated Dictionary of Electronics

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AFIPS • aircraft bonding 17

AFIPS Acronym for American Federation of Infor- airborne intercept radar A type of short-range
mation Processing Societies. radar used aboard fighter and interceptor aircraft
afpc Abbreviation of automatic frequency/phase for tracking their targets.
control. airborne long-range input Equipment aboard air-
AFSK Abbreviation of AUDIO-FREQUENCY-SHIFT craft, for the purpose of facilitating the use of
KEYING. long-range missiles.
afterglow The tendency of the phosphor of a cath- airborne noise See ACOUSTIC NOISE.
ode-ray-tube screen to glow for a certain time af- airborne radar platform Surveillance and alti-
ter the cathode-ray beam has passed. Also see tude-finding radar used aboard aircraft.
PERSISTENCE. air capacitor A capacitor in which air is the dielec-
afterpulse An extraneous pulse in a multiplier tric between two sets of conductive plates. Also
phototube (photomultiplier), induced by a pre- called air-dielectric capacitor.
ceding pulse. aircarrier aircraft station On an aircraft, a radio
AF transformer See AUDIO-FREQUENCY TRANS- station that is involved in carrying people for hire
FORMER. or in transporting cargo.
a/g Abbreviation of AIR-TO-GROUND. air cell A primary electrochemical cell in which the
AGC Abbreviation of AUTOMATIC GAIN CONTROL. positive electrode is depolarized by reduced oxy-
AGE Abbreviation of AEROSPACE GROUND gen in the air.
EQUIPMENT. air cleaner See DUST PRECIPITATOR.
agent An active force, condition, mechanism, or air column The open space inside an acoustic
substance that produces or sustains an effect. chamber, pipe, or horn.
Thus, a sudden voltage rise is a triggering agent air-cooled component A component, such as a
in certain bistable circuits; arsenic is a doping power transistor, that is cooled by circulating air,
agent in semiconductor processing; the slow cool- compared with one cooled by a circulating liquid,
ing of a heated metal to improve ductility is an such as water or oil.
ANNEALING AGENT. air-cooled transistor A transistor (particularly a
aging 1. An initial run of a component or circuit power transistor) from which the heat of opera-
over a certain period of time shortly after manu- tion is drawn away, through radiation and con-
facture to stabilize its characteristics and per- vection, into the surrounding air. The transistor
formance. 2. The changing of electrical is usually mounted on a heatsink or fitted with
characteristics or of chemical properties over a fins.
protracted period of time. air-cooled tube An electron tube from which heat
agonic line An imaginary line connecting points on is drawn away, mainly via convection, into the
the earth’s surface at which a magnetic needle surrounding air. A device called a chimney can be
shows zero declination (i.e., points to true geo- placed around the tube, through which air is
graphic north). blown by a fan. Cool air enters through the bot-
AGREE Acronym for Advisory Group on Reliability tom of the assembly, and hot air escapes from the
of Electronics Equipment. top.
Ah Abbreviation of AMPERE-HOUR. Depending on air-core inductor A coil of wire wound around a
the standard used, the abbreviation can be amp- hollow cylindrical form or in a loop, designed to
hr, a-h, a-hr, or A-h. introduce inductive reactance into a circuit or
aH Abbreviation of ATTOHENRY. system. In practice, the maximum attainable in-
aided tracking In radar and fire control, a system ductance is approximately 1 mH. This type of in-
in which manual correction of target tracking er- ductor is used in some wireless transmitters,
ror automatically corrects the rate of movement receivers, and antenna networks. The component
of the tracking mechanism. can be designed for high current-carrying capac-
AIEE Abbreviation for American Institute of Electri- ity by using heavy-gauge wire and a large winding
cal Engineers, now consolidated with the IRE, radius. The magnetic lines of flux extend consid-
forming the IEEE. erably beyond the interior of the coil, especially
AIP Abbreviation for American Institute of Physics. along the winding axis. This increases the likeli-
air The mixture of gases that constitutes the hood of mutual inductance between the coil and
earth’s atmosphere and figures prominently in surrounding electrical components, devices, or
the manufacture and operation of numerous circuits.
electronic devices. By volume, air contains about air-core transformer A transformer without a fer-
21 percent oxygen, 78 percent nitrogen, and romagnetic core, so called because air is the only
lesser amounts of argon, carbon dioxide, helium, material at the center of (and immediately sur-
hydrogen, krypton, neon, and xenon. It also con- rounding) the transformer coils.
tains varying amounts of water vapor, and in aircraft bonding The practice of solidly connect-
smoggy areas, carbon monoxide and the oxides of ing, for electrical purposes, the metal parts of an
sulfur and nitrogen. aircraft, including the engine.