18WuD2x

182 diagnostic routine • diamond lattice
diagnostic routine 1. An efficient sequence of diagnostic
tests for rapid, foolproof trouble-shooting
of electronic hardware. 2. A computer
software package intended for debugging
programs, or for finding the cause of a hardware
or operating-system malfunction. Also called
diagnostic, diagnostic program, or diagnostic
utility.
diagnostic test 1. A test made primarily to
ascertain the cause of dysfunction in electronic
equipment. Compare PERFORMANCE TEST. 2.
To apply a diagnostic routine to hardware faults,
or to implement one to prevent such a fault.
diagnotor In digital computer operations, a troubleshooting
routine combining both diagnosis
and editing.
diagram A (usually line) drawing depicting a circuit,
assembly, or organization. See, for example,
BLOCK DIAGRAM and CIRCUIT DIAGRAM.
dial 1. A graduated scale, arranged horizontally,
vertically, in a circle, or over an arc. Used to show
the distance through which a variable component
(such as a potentiometer, variable capacitor, or
switch) has been adjusted. A pointer can move
over the scale, or the scale can be moved past a
stationary pointer. 2. The graduated face of a meter.
3. In a telephone system, to press the keys or
actuate the tones that establish contact with another
subscriber.
dial cable A flexible cable or belt conveying motion
on the shaft of an adjustable component (such as
a potentiometer or variable capacitor) to a dial.
dial-calibrated attenuator A variable attenuator
with a dial reading directly in decibels.
dial-calibrated capacitor A variable capacitor
with a dial reading directly in picofarads.
dial-calibrated inductor A variable inductor with
a dial reading directly in microhenrys.
dial-calibrated potentiometer A potentiometer
with a dial reading directly in output volts,
percentage of input voltage, number of turns
(when resistance is a linear function), or other
quantity.
dial-calibrated resistor A variable resistor with a
dial reading directly in ohms, kilohms, or
megohms.
dial-calibrated rheostat See DIAL-CALIBRATED
RESISTOR.
dial cord A form of dial cable. Cord usually designates
a fabric string, whereas a cable is a flexible,
braided wire.
dial knob The knob used to turn a dial under a
pointer, or to turn a pointer over a dial scale.
dial lamp See DIAL LIGHT.
dial light A small lamp sometimes used to illuminate
a dial. Can also serve as a pilot light.
dial lock A small mechanism used to lock a dial at
a particular setting to prevent further turning.
dialer See AUTOMATIC DIALING UNIT.
dialing key In a telephone system, a dial that uses
keys, rather than a rotary dial.
dial jack In a telephone system, a set of jacks that
facilitates interconnections between dial cords
and external lines.
dial light A lamp or light-emitting diode placed in
the dial mechanism of a radio receiver, transmitter,
or transceiver. Allows the dial to be read in
dim light or in darkness.
dialog equalizer In sound transmission and recording,
a high-pass filter that reduces lowfrequency
response during dialog and extreme
closeups.
dial pulse An interruption of the direct current in a
telephone system when the dial contacts of the
calling telephone open. The number of such interruptions
corresponds to the digit dialed.
dial scale The graduated portion of a dial.
dial system 1. See DIAL TELEPHONE SYSTEM.
2. The arrangement of dials and knobs that facilitates
adjustment of electronic equipment.
dial telephone A telephone set in which a numbered
rotatable disk is used to produce the switch
interruptions that cause generation of the transmitted
multidigit telephone numbers.
dial telephone system The complete automatic
circuit, including central-office facilities, for dial
telephone operation.
dial tone In a telephone system, a constant hum or
whine heard before dialing, indicating that the
system is operational.
dial-up In a telephone system, the calling of one
subscriber by another, using a dial system.
diam Abbreviation of diameter.
diamagnetic Pertaining to a material having magnetic
permeability less than unity.
diamagnetism The state of having magnetic permeability
less than unity. A material with this property
reduces the flux density of a magnetic field,
relative to the flux density in air or in free space.
diamond antenna Also called rhombic antenna.
A nonresonant wideband directional antenna
whose horizontal wire elements are arranged in
the shape of a diamond (rhombus). The arrangement
is fed at one corner, the opposite corner being
terminated with a noninductive resistor.
diamond lattice The orderly internal arrangement
of atoms in a redundant pattern in crystalline
materials, such as germanium or silicon.
Feed
Line
x
x
x
x
All sides x are equal
x ≥ 1 λ
diamond antenna
≈ 600 Ω
Maximum
radiation