18WuD2x

circular mil • class-A amplifier 117
Conductor
carrying ac
circular magnetic wave
Magnetic lines
of flux
circular mil A unit of cross-sectional area equivalent
to 0.785 millionths of a square inch, or the
area of a circle having a diameter of 0.001 inch.
Generally, the circular mil is used to specify the
cross-sectional area of a conductor, such as wire.
circular mil foot A unit of volume in which the
length is 1 foot and the cross-sectional area is 1
circular mil.
circular polarization A form of electromagneticwave
polarization in which the orientation of the
electric flux rotates continuously and uniformly
as the wave propagates through space. Circular
polarization can occur in either a clockwise or
counterclockwise sense.
circular radian The angle enclosed by two radii of
a unit circle and subtended by a unit arc. Equal
to about 57.296 angular degrees.
circular scan A radar scan in which the electronbeam
spot describes a circle centered around the
transmitting antenna.
circular sweep In an oscilloscope, a sweep obtained
when the horizontal and vertical sinusoidal
deflecting voltages have the same
amplitude and frequency, but are out of phase by
90 degrees (1 ⁄4 cycle).
circular trace An oscilloscope pattern consisting
of a circle obtained with a circular sweep of the
electron beam.
circular waveguide A waveguide with a circular
cross section.
circulating register In a digital computer, a register
in which digits are taken from locations at one
end and returned to those at the other end.
circulating tank current The alternating current
that oscillates between the capacitor and inductor
within a tank circuit.
circulator A multi-terminal coupler in which microwave
energy is transmitted in a particular direction
from one terminal to the next.
circumvention In a security or alarm system, the
evasion of detection. Can be done by physically
avoiding regions of coverage, or by defeating the
system electronically.
cis A prefix meaning “on this side of.” For example,
the cislunar field is the field on this side of the
moon.
Citizen Band Abbreviation, CB. A band of radio
frequencies allocated for two-way communication
between private citizens (apart from amateur and
commercial services).
Citizens Radio Service Two-way radio communication
in a CITIZEN BAND. In the United States,
the FCC licenses users of this service without requiring
them to take an examination.
C/kg Abbreviation of coulombs per kilogram, the
unit for electron charge-to-mass ratio.
C/kmol Abbreviation of coulombs per kilomole, the
unit for the Faraday constant.
ckt Abbreviation of CIRCUIT.
Cl Symbol for CHLORINE.
cl Abbreviation of CENTILITER.
cladding The bonding of one metal to another to
minimize or prevent corrosion. A common example
is copper-clad steel wire, ideal for use in
radio-frequency antenna systems. The copper
provides excellent conduction, and the steel provides
high tensile strength with a minimum of
wire stretching.
clamper A device that restricts a wave to a predetermined
dc level. Also called DC RESTORER.
clamping 1. Fixing the operation of a device at a
definite dc level. Also see CLAMPER. 2. In television,
establishing a fixed level for the picture signal
at the start of each scanning line.
clamping circuit See CLAMPER.
clamping diode A diode used to fix the voltage
level of a signal at a particular reference point.
clapper In a bell, the ball or hammer that strikes
the bell; in an electric bell, it is affixed to the vibrating
armature.
Clapp-Gouriet oscillator A Colpitts oscillator in
which a capacitor is connected in series with the
inductor. The circuit offers high frequency stability
in the presence of input and output capacitance
variations.
Clapp oscillator A series-tuned hybrid Colpitts oscillator,
having a tuning capacitor in series with
the inductor, rather than in parallel with the inductor.
The circuit allows the use of a smaller
tuning capacitor, resulting in improved stability.
Clark cell See ZINC STANDARD CELL.
class-A amplifier An amplifier whose bias is set at
approximately the midpoint of the characteristic
curve. Output electrode current flows during the