18WuD2x

98 capacitor • carbon-button amplifier
capacitor A passive electronic-circuit component
consisting of, in basic form, two metal electrodes
or plates separated by a dielectric (insulator).
capacitor amplifier See DIELECTRIC AMPLIFIER.
capacitor antenna See CONDENSER ANTENNA.
capacitor bank A network of capacitors connected
in combination, yielding a desired characteristic.
capacitor braking The connection of a capacitor to
the winding of a motor after the removal of power,
to speed up the process of braking.
capacitor color code See COLOR CODE.
capacitor decade See DECADE CAPACITOR.
capacitor-discharge ignition CAPACITIVE-
DISCHARGE IGNITION.
capacitor filter In a direct-current power supply, a
filter consisting simply of a capacitor connected
in parallel with the rectifier output.
+
Pulsating
dc input
−
+
capacitor filter
+
Pure
dc output
capacitor-input filter A filter whose input component
is a capacitor. The capacitor-input powersupply
filter is distinguished by its relatively high
dc output voltage, but somewhat poorer voltage
regulation, compared with the CHOKE-INPUT
FILTER.
capacitor leakage Direct current flowing through
the dielectric of a capacitor. In a good nonelectrolytic
capacitor, this current is normally less
than 1 microampere. In an electrolytic capacitor,
it can be up to several milliamperes, depending
on the capacitance and the applied voltage.
capacitor loudspeaker See ELECTROSTATIC
SPEAKER.
capacitor microphone See CONDENSER MICRO-
PHONE.
capacitor motor An ac motor that uses a capacitor
in series with an auxiliary field winding for
starting purposes. Initially out-of-phase current
in the auxiliary field (starting winding) causes a
rotating field that turns the rotor. When the rotor
reaches a safe speed, a centrifugal switch disconnects
the capacitor and auxiliary field, and
the motor continues running as an induction
motor.
capacitor series resistance The ohmic loss in
a capacitor. It results partly from conductor
losses, and partly from losses in the dielectric
material.
capacitor substitution box An enclosed assortment
of selected-value capacitors arranged to be
switched one at a time to a pair of terminals. In
troubleshooting and circuit development, any of
−
several useful fixed capacitance values can be
thus obtained.
capacitor voltage 1. The voltage at the terminals
of a capacitor. 2. The maximum voltage rating of
a capacitor.
capacitor voltmeter See ELECTROSTATIC VOLT-
METER.
capacity 1. A measure of a cell’s or battery’s ability
to supply current during a given period. 2. CA-
PACITANCE. 3. The number of bits or bytes a
computer storage device can hold. 4. The limits of
numbers that a register can process.
capacity lag In an automatic control system, a delay
caused by the storing of energy by the components.
For example, in a heating system, capacity
lag results from the time taken to heat the air or
fluid after the thermostat turns on the heat.
capillary electrometer A sensitive voltage indicator,
consisting of a column of mercury in a
transparent capillary tube, in which is suspended
a small drop of acid. When a voltage is
applied to both ends of the mercury column, the
acid drop moves toward the low-potential end of
the column over a distance proportional to the
voltage.
capstan The driven spindle or shaft of a magnetic
tape recorder or transport.
capture area The effective ability of a radio antenna
to pick up electromagnetic signals. The larger the
capture area, the greater the antenna gain.
capture effect 1. In frequency-modulation (FM)
radio receivers, the effect of domination by the
stronger of two signals, or by the strongest of several
signals, on the same frequency. 2. In an
automatic-frequency-control system, the tendency
of the receiver to move toward the strongest of
several signals near a given frequency. 3. In general,
the tendency of one effect to totally predominate
over other effects of lesser amplitude.
capture ratio A measure of frequency-modulation
(FM) tuner selectivity: The amplitude difference,
in decibels, between unwanted signals and the
one being tuned in.
carbon Symbol, C. A nonmetallic element. Atomic
number, 6. Atomic weight, 12.011. Carbon, besides
being an invaluable material in electronics,
is an important constituent of organic compounds.
carbon arc The arc between two electrified pencils
of carbon or, as in an arc converter, between a
carbon pencil and a metal electrode.
carbon brush A contact made of carbon or some
mixture of carbon and another material, used in
motors, generators, variable auto-transformers,
rheostats, and potentiometers.
carbon-button amplifier An audio-frequency
amplifier having as the active component an
earphone whose diaphragm is attached to a carbon
microphone button. The input signal applied
to the earphone makes its diaphragm
vibrate. The vibrating button modulates a local