1-4
ANTISEIZE COMPOUND—A silicon-based, high-temperature lubricant applied to threaded components
to aid in their removal after they have been subjected to rapid heating and cooling [4].
ANTITRANSMIT-RECEIVE TUBE (atr)—A tube that isolates the transmitter from the antenna and
receiver. Used in conjunction with a tr tube [18].
APERTURE—See SLOT [11].
APOGEE—The point in the orbit of a satellite the greatest distance from the earth [17].
APPARENT DRIFT—The effect of the earth's rotation on a gyro that causes the spinning axis to appear to
make one complete rotation in one day. Also called APPARENT PRECESSION or APPARENT
ROTATION [15].
APPARENT POWER—That power apparently available for use in an ac circuit containing a reactive
element. It is the product of effective voltage times effective current expressed in volt-amperes. It must
be multiplied by the power factor to obtain true power available [2].
APPARENT PRECESSION—See APPARENT DRIFT [15].
APPARENT ROTATION—See APPARENT DRIFT [15].
ARC EXTINGUISHER—The part of a circuit breaker that confines and divides the arc which occurs when
the contact of the circuit breaker opens [3].
ARMATURE—(1) In a relay, the movable portion of the relay [3]. (2) The windings in which the output
voltage is generated in a generator or in which input current creates a magnetic field that interacts with
the main field in a motor [5].
ARMATURE LOSSES—Copper losses, eddy current losses, and hysteresis losses that act to decrease the
efficiency of armatures [5].
ARMATURE REACTION—The effect in a dc generator of current in the armature creating a magnetic
field that distorts the main field and causes a shift in the neutral plane [5].
ARRAY OF ARRAYS—Same as COMBINATION ARRAY [10].
ARTIFICIAL TRANSMISSION LINE—An LC network that is designed to simulate characteristics of a
transmission line [18].
ASBESTOS—A noncombustible, nonconductive, fiber-like mineral used as an insulating material [4].
ASBESTOSIS—Fibrosis of the lungs caused by inhalation of asbestos fibers [4].
A-SCOPE—A radar display on which slant range is shown as the distance along a horizontal trace [18].
ASSEMBLY—A number of parts or subassemblies, or any combination thereof, joined together to perform
a specific function [17].
ASTABLE MULTIVIBRATOR—A multivibrator that has no stable state. Also called free-running
because it alternates between two different output voltage levels during the time it is on. The frequency
is determined by the RC time constant of the coupling circuit [9].
ASWTDS—An abbreviation for the antisubmarine warfare tactical data system [17].
