ANTISEIZE COMPOUNDA silicon-based, high-temperature lubricant applied to threaded components
to aid in their removal after they have been subjected to rapid heating and cooling .
ANTITRANSMIT-RECEIVE TUBE (atr)A tube that isolates the transmitter from the antenna and
receiver. Used in conjunction with a tr tube .
APERTURESee SLOT .
APOGEEThe point in the orbit of a satellite the greatest distance from the earth .
APPARENT DRIFTThe 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
APPARENT POWERThat 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 .
APPARENT PRECESSIONSee APPARENT DRIFT .
APPARENT ROTATIONSee APPARENT DRIFT .
ARC EXTINGUISHERThe part of a circuit breaker that confines and divides the arc which occurs when
the contact of the circuit breaker opens .
ARMATURE(1) In a relay, the movable portion of the relay . (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 .
ARMATURE LOSSESCopper losses, eddy current losses, and hysteresis losses that act to decrease the
efficiency of armatures .
ARMATURE REACTIONThe 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 .
ARRAY OF ARRAYSSame as COMBINATION ARRAY .
ARTIFICIAL TRANSMISSION LINEAn LC network that is designed to simulate characteristics of a
transmission line .
ASBESTOSA noncombustible, nonconductive, fiber-like mineral used as an insulating material .
ASBESTOSISFibrosis of the lungs caused by inhalation of asbestos fibers .
A-SCOPEA radar display on which slant range is shown as the distance along a horizontal trace .
ASSEMBLYA number of parts or subassemblies, or any combination thereof, joined together to perform
a specific function .
ASTABLE MULTIVIBRATORA 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 .
ASWTDSAn abbreviation for the antisubmarine warfare tactical data system .