18WuD2x

contactor noise • Continuous Commercial Service 143
Movable
magnet
Fixed coil
Output
Diaphragm
contact microphone
Object carrying
sound disturbance
closed. 2. Sounds coming directly from contacts
that are opening and closing.
contact potential The small direct-current (dc)
voltage that results from the bombardment of an
electrode by electrons, when the electrode has no
external voltage applied to it.
contact pressure The pressure that holds contacts
together.
contact protector A component (such as a diode,
capacitor, resistor, or combination of these) that
serves to suppress contact arcing.
contact rating The maximum current, voltage,
and/or power specified for a given set of contacts.
contact rectifier A rectifier consisting of two dissimilar
materials in direct contact. Examples:
copper and copper oxide, magnesium and copper
sulfide, selenium and aluminum, and germanium
and indium.
contact resistance The resistance of the closed
contacts of switches, relays, and other similar devices.
Normally, this is a very small resistance.
contact separation See CONTACT GAP.
contact strip See TERMINAL STRIP.
contact switch An electromechanical switch that
uses contacts to make and break a circuit, as
compared with an electronic switch that uses
semiconductor devices.
contact travel The distance over which a relay or
switch contact must move to close a circuit.
contact wetting The use of mercury (a conducting
liquid) to improve the action of a relay contact or
contacts.
contact wipe A sliding motion between closed contacts.
Helps to establish a good connection and to
keep the contact surfaces clean.
container file See CONTROLLING FILE.
contaminated material 1. A semiconductor material
containing some undesired substance. 2. A
material unintentionally made radioactive.
contamination 1. The presence of an impurity in a
substance. 2. The addition of a radioactive material
to a substance. 3. In a coaxial cable, the tendency
for the jacket material to bleed through the
outer braid into the dielectric, resulting in increased
loss.
content-addressed storage In a computer, memory-
or data-storage locations identified by content
(see CONTENTS), instead of by address. Also
called associative storage.
contention The result of interference among more
than one transmitting station on the same communications
channel.
contents 1. The data in a computer randomaccess
memory (RAM). 2. The data in a specific
storage location, such as on a hard disk, diskette,
or CD-ROM.
context 1. The environment in which a word is
used in a natural language (such as English,
Spanish, or Russian). Important in speech
recognition and speech synthesis. 2. The environment
in which a string of characters, composing
a data unit or word, is used in a
computer program.
Continental code A version of the Morse code
used internationally in radiotelegraphy. Also
called International Morse code and general service
code. Compare AMERICAN MORSE CODE.
continuity A condition of being uninterrupted—
especially pertaining to current flowing in an
electrical or electronic circuit.
continuity test A test of the completeness of an
electrical path. Ideally, the only concern is
whether the circuit is open or closed, but sometimes
circuit resistance is also of interest.
continuity tester A device (such as an ohmmeter,
battery and buzzer, and battery and lamp) with
which a continuity test can be made.
continuity writer The person who prepares copy
for a radio or television broadcaster.
continuous carrier A medium (such as a radiofrequency
wave) that will convey information (as
when the carrier is modulated) with no disruption
of the medium itself.
continuous circuit An uninterrupted circuit.
Continuous Commercial Service Abbreviation,
CCS. A category in which safe operating parameters
are listed for electronic components and
communications equipment operated over long,
uninterrupted periods. Compare INTERMITTENT
COMMERCIAL AND AMATEUR SERVICE.