18WuD2x

148 coordinate system • cordless modem
coordinate system A mathematical means of
uniquely defining or locating a point on a line, in
a plane, or in space. The most common coordinates
are CARTESIAN COORDINATES (also
called rectangular coordinates), consisting of
numbered lines intersecting at right angles.
6
4
2
−6 −4 −2 2 4 6
−2
−4
−6
y
coordinate system
(Cartesian)
coordination complex An ion or compound having
a central (usually metallic) ion combined by
coordinate bonds with a definite number of surrounding
groups, ions, or molecules.
coplanar array A set of antennas that lie in the
same plane, and are fed by a common transmission
line.
copper Symbol, Cu. A metallic element. Atomic
number, 29. Atomic weight, 63.546. An excellent
conductor of electricity and heat, commonly used
in the manufacture of wires and cables.
copper-clad wire Iron or steel wire plated with
copper.
copper-constantan thermocouple A thermocouple
consisting of a junction between wires or
strips of copper and constantan. Typical output
is 4.24 mV at 100°C.
copper loss Power (I 2 R) loss in copper wires, cables,
and/or coils.
copper-oxide diode A small diode in which the
semiconductor material is copper oxide. Such
diodes, widely used before the ready availability
of selenium and silicon, are still occasionally
found in meter-rectifier service.
copper-oxide modulator An amplitude modulator
whose action is derived from the nonlinear conduction
characteristic of copper-oxide diodes.
copper-oxide photocell A photoelectric cell in
which the light-sensitive material is copper oxide.
copper-oxide rectifier A rectifier in which the
semiconductor material is copper oxide. Rectifiers
of this type are suitable for low-voltage ser-
x
vice; they were widely used before the advent of
germanium, silicon, and selenium rectifiers.
copper pyrites See CHALCOPYRITE.
copper-sulfide rectifier A rectifier in which the
unilateral junction is between copper-sulfide and
magnesium elements. Like the copper-oxide rectifier,
the copper-sulfide unit was once widely
used in low-voltage applications.
copy 1. Also called hard copy. Printed or written
text. 2. In communications, a qualitative expression
of the extent to which received data is intelligible
(e.g., a radio operator’s signal report, “You
are solid (perfect) copy.”). 3. To duplicate data in
a storage system, the original being in another
system, or in a different location in the same
system. 4. An exact duplicate of data in any
form.
copying telegraph A descriptive term for a facsimile
system.
Corbino disk A variable resistor consisting of a
semiconductor disk capable of exhibiting the
CORBINO EFFECT. The disk is inserted into an
adjustable magnetic field, which serves as the
control medium.
Corbino effect A phenomenon similar to the HALL
EFFECT, in which a current flows around a disk
carrying a radial current when the disk is inserted
into a magnetic field whose lines of flux are
perpendicular to the disk. Compare HALL EF-
FECT.
Semiconductor
disk
+
Magnetic
field
Corbino effect
Current
flow
cord 1. A length of flexible, insulated cable, usually
having two or three conductors. 2. Tough, insulating
string (e.g., dial cord or lacing cord).
cordless 1. Descriptive of a plug without a flexible
cord. 2. Pertaining to radio-frequency (RF) or infrared
short-range links for communications and
control (e.g., a cordless telephone set).
cordless keyboard A computer keyboard that employs
an infrared (IR), very-high frequency (VHF),
or ultra-high-frequency (UHF) transmitter and receiver.
Commonly used with so-called Web TV
systems and in presentations using a display projection
system. Operates according to the same
electronic scheme as a CORDLESS MOUSE.
cordless modem See WIRELESS MODEM, 3.
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