Browse the glossary using this index

Special | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | ALL

Page:  1  2  3  4  5  6  7  8  9  (Next)
  ALL

A

A-SCOPE

A radar display on which slant range is shown as the distance along a horizontal trace [18].

ABSORPTION

(1) Dissipation of radio or sound waves as they interact with matter. (2) The absorbing of light waves without reflection or refraction [10].


ABSORPTION WAVEMETER

An instrument used to measure audio frequencies [16].

ACCELERATING ANODE

An electrode charged several thousand volts positive and used to accelerate
electrons toward the front of a cathode-ray tube [6].


ACCELERATION SERVOSYSTEM

A servosystem that controls the acceleration (rate of change in velocity) of a load [15].


ACCELEROMETER

A device that measures the acceleration to which it is subjected and develops a
signal proportional to it [15].


ACCEPTOR IMPURITY

An impurity which, when added to a semiconductor, accepts one electron from
a neighboring atom and creates a hole in the lattice structure of the crystal. Also called TRIVALENT
IMPURITY [7].


ACORN TUBE

A very small tube with closely spaced electrodes and no base. The tube is connected to its circuits by short wire pins that are sealed in a glass or ceramic envelope. The acorn tube is used in low-power uhf circuits [6].


ACOUSTICS

The science of sound [10].

ACQUISITION

Operational phase of a fire-control or track radar during which the radar system searches a small volume of space in a prearranged pattern [18].


ACTIVE SATELLITE

A satellite that amplifies the received signal and retransmits it back to earth [17].

ACTUATOR

The part of a switch that is acted upon to cause the switch to change contact connections; for example, toggle, pushbutton, and rocker [3].


AFDS

An abbreviation for the amphibious flagship data system [17].

AIR-CONTROL PANEL

Panel that monitors the dry-air input at each user equipment [18].

AIR-CORE TRANSFORMER

A transformer composed of two or more coils that are wound around a
nonmetallic core [2].


ALLOYED JUNCTION

A junction formed by recrystallization of a molten region of P-type material on
an N-type substrate, or vice versa [7].


ALPHA

The emitter-to-collector current gain in a common-base circuit [7].

ALTERNATING CURRENT

An electrical current that constantly changes amplitude and changes
polarity at regular intervals [2].


ALTITUDE

The vertical distance of an aircraft or object above a given reference, such as ground or sea level [18].


ALUMINUM CREEP

(1) The movement of aluminum wire from a point where pressure is applied. (2)
The "retreat" of heated aluminum wire as it cools [4].


AMBIENT TEMPERATURE

The surrounding temperature such as the temperature of air surrounding a
conductor in a compartment or within a piece of equipment [4].


AMBIGUOUS RETURNS

Echoes that exceed the prt of a radar and appear at incorrect ranges [18].

AMMETER

An instrument for measuring the amount of electron flow (in amperes) [1] [3] [6].

AMPERE

The basic unit of electrical current [1].

AMPERE-TURN

The magnetomotive force developed by 1 ampere of current flowing through a coil of one turn [8].


AMPERITE (BALLAST) TUBE

A current-controlling resistance device designed to maintain
substantially constant current over a specified range of variation in applied voltage or resistance of a
series circuit [6].


AMPLIDYNE

A special dc generator in which a small dc voltage applied to field windings controls a large output voltage from the generator. In effect, an amplidyne is a rotary amplifier that often times produces gain of approximately 10,000 [5].


AMPLIFICATION

(1) The process of enlarging a signal in amplitude (as of voltage or current) [8]. (2) The ratio of output magnitude to input magnitude in a device that is intended to produce an output that is an enlarged reproduction of its input [6] [7].


AMPLIFICATION FACTOR

The voltage gain of an amplifier with no load on the output [6] [7].

AMPLIFIER

AMPLIFIER—The device that provides amplification (the increase in current, voltage, or power of a signal) without appreciably altering the original signal [7] [8].


AMPLITRON

AMPLITRON—See CROSS-FIELD AMPLIFIER [18].

AMPLITUDE

AMPLITUDE—The size of a signal as measured from a reference line to a maximum value above or below the line. Generally used to describe voltage, current, or power [8] [12].


AMPLITUDE DISTORTION

AMPLITUDE DISTORTION—Distortion that is present in an amplifier when the amplitude of the output signal fails to follow exactly any increase or decrease in the amplitude of the input signal [6] [7].


AMPLITUDE MODULATION

AMPLITUDE MODULATION—Any method of varying the amplitude of an electromagnetic carrier frequency in accordance with the intelligence to be transmitted [12].


AMPLITUDE STABILITY

AMPLITUDE STABILITY—Amplitude stability refers to the ability of the oscillator to maintain a constant amplitude in the output waveform [9].


AND CIRCUIT

AND CIRCUIT—See AND GATE [13].

AND GATE

AND GATE—(1) An electronic gate whose output is energized only when every input is in its prescribed state. An AND gate performs the function of the logical "AND"; also called an AND circuit. (2) A binary circuit, with two or more inputs and a single output, in which the output is a logic 1 only when all inputs are a logic 1 and the output is a logic 0 when any one of the inputs is a logic 0 [13].


ANGLE MODULATION

Modulation in which the angle of a sine-wave carrier is varied by a modulating
wave [12].


ANGLE OF INCIDENCE

The angle between the incident wave and the normal [10].

ANGLE OF INCLINATION

The angular difference between the equatorial plane of the earth and the
plane of orbit of the satellite [17].


ANGLE OF REFLECTION

The angle between the reflected wave and the normal [10].

ANGLE OF REFRACTION

The angle between the normal and the path of a wave through the second
medium [10].


ANGSTROM UNIT

The unit used to define the wavelength of light waves [10].

ANISOTROPIC

The property of a radiator that allows it to emit strong radiation in one direction [10].

ANODE

(1) A positive electrode of an electrochemical device (such as a primary or secondary electric cell) toward which the negative ions are drawn [1] [6) [7]. (2) The semiconductor-diode terminal that is positive with respect to the other terminal when the diode is biased in the forward direction [13].


ANTENNA

A conductor or set of conductors used to radiate RF energy into space or to collect RF energy from space or to do both [10].


ANTENNA BEAM WIDTH

Width of a radar beam measured between half-power points [18].

ANTENNA COUPLER

A device used for impedance matching between an antenna and a transmitter or receiver [17].


ANTENNA SYSTEM

Routes RF energy from the transmitter, radiates the energy into space, receives
echoes, and routes the echoes to the receiver [18].


ANTIJAMMING CIRCUIT

An electronic circuit used to minimize the effects of enemy countermeasures, thereby permitting radar echoes to be visible on the indicator [18].


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].


APERTURE

APERTURE—See SLOT [11].

APL

ALLOWANCE PARTS LIST (APL)—Repair parts required for units having the equipment/ component listed [14].


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

APPARENT PRECESSION—See APPARENT DRIFT [15].

APPARENT ROTATION

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

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].

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].

ASYMMETRICAL MULTIVIBRATOR

A multivibrator that generates rectangular waves [18].

ASYNCHRONOUS

The teletypewriter operation where the transmitter and receiver do not operate continuously [17].


ASYNCHRONOUS ORBIT

One where the satellite does not rotate or move at the same speed as the
earth [17].


ATDS

An abbreviation for the airborne tactical data system [17].

atr

A tube that isolates the transmitter from the antenna and receiver. Used in conjunction with a tr tube [18].


ATTENUATION

The ability of a filter circuit to reduce the amplitude of unwanted frequencies to a level below that of the desired output frequency [9].


ATTRACTION

The force that tends to make two objects approach each other. Attraction exists between two unlike magnetic poles (north and south) or between two unlike static charges [1].


AUDIO AMPLIFIER

An amplifier designed to amplify frequencies between 15 hertz (15 Hz) and 20
kilohertz (20 kHz) [8].


AUDIO-FREQUENCY-TONE SHIFT

A system that uses amplitude modulation to change dc mark and
space impulses into audio impulses [17].


AUTOMATIC GAIN CONTROL

A circuit used to vary radar receiver gain for best reception of signals that have widely varying amplitudes [18].


AUTOMATIC TRACKING

Tracking done by equipment that compares the direction of the antenna axis
and the direction of the received signal and uses the difference (error) signal to reposition the antenna [17].


AUTOMATIC VOLUME/GAIN CONTROL

A circuit used to limit variations in the output signal strength of a receiver [17].


AVALANCHE EFFECT

A reverse breakdown effect in diodes that occurs at reverse voltages beyond 5
volts. The released electrons are accelerated by the electric field, which results in a release of more electrons in a chain or "avalanche" effect [7].


AVERAGE POWER

(1) The peak power value averaged over the pulse-repetition time [12]. (2) Output power of a transmitter as measured from the start of one pulse to the start of the next pulse [18].


AVERAGE VALUE

The average of all the instantaneous values of one-half cycle of alternating
current [2].


AWG

The standards adopted in the United States for the measurement of wire sizes [4].


AXIS

A straight line, either real or imaginary, passing through a body around which the body revolves
[15].


AZIMUTH

Angular measurement in the horizontal plane in a clockwise direction [18].


Page:  1  2  3  4  5  6  7  8  9  (Next)
  ALL