18WuD2x

666 susceptance • swing
susceptance Symbol, B. Unit, siemens. The reactive
component of admittance, as distinguished
from conductance.
susceptibility The capacity of a substance to become
magnetized, expressed as the ratio of magnetization
to the strength of the magnetizing
force.
suspension 1. In a speaker, the flexible, circular or
elliptical structure via which the cone is attached
to the frame. 2. The wire or metallized fiber
supporting the movable coil of a galvanometer.
3. Particles of a substance and the liquid in which
it is mixed, but not dissolved. 4. The substance,
as defined in 3.
suspension galvanometer A meter with a lightbeam
apparatus for lengthening the arc through
which the pointer travels. When the beam of light
is cast a long distance, a tiny movement of the
coil will cause considerable movement of the image.
sustained oscillations Oscillations that continue
as long as power is supplied to the oscillation
generator. Also see CONTINUOUS WAVE. Compare
DAMPED OSCILLATIONS.
sustaining voltage The voltage at which secondcollector
breakdown occurs in a transistor (see
SECOND BREAKDOWN).
S video In animation, a scheme that separates
brightness and color. It can enhance the video in
some applications.
SW Abbreviation of SHORTWAVE.
sw Abbreviation of SWITCH. (Also, S or s.)
swamping resistor 1. A noninductive resistor connected
in parallel with the input circuit of a class-
B linear amplifier for automatic regulation of the
excitation. 2. A resistor connected in series with
the emitter of a bipolar transistor to minimize the
effects of temperature-induced variations in junction
resistance.
swarf The string of material that threads off a disc
during sound recording.
S W band A section of the S BAND, extending from
3400 to 3700 MHz.
sweep 1. To deflect the electron beam in a cathoderay
tube, usually horizontally, to provide a time
base. 2. The circuit for achieving the particular
deflection described in 1.
sweep circuit A circuit, such as a deflection generator
(e.g., a sawtooth oscillator), for producing a
sweep signal. Also see SWEEP.
sweep delay In an oscilloscope, the process of initiating
the sweep of the electron beam at some selected
instant after the signal has started.
sweep-delay circuit In an oscilloscope or radar,
the circuit for delaying the sweep until the start of
the signal. Also see DELAYED SWEEP.
sweeper 1. See SWEEP GENERATOR. 2. See
SWEEP-SIGNAL GENERATOR.
sweep frequency 1. The frequency at which the
electron beam in a cathode-ray tube is deflected
along the reference axis. 2. The frequency at
which the carrier frequency is increased and decreased
by a sweep-signal generator. 3. In an oscilloscope,
the number of times that the trace
moves across the screen in one second. It is equal
to the reciprocal of the SWEEP PERIOD.
sweep generator 1. A device that causes the electron
beam in a cathode-ray tube to scan at a
known speed. 2. An oscillator that generates a
signal that rapidly varies in frequency. It is used
for the testing and adjustment of bandpass filters
and other selective circuits.
sweeping receiver See SCANNING RECEIVER.
sweep magnification In an oscilloscope, increasing
or multiplying the sweep frequency, thus reducing
the time per horizontal division. This
increases the maximum frequency of waveforms
that can be analyzed, and allows closer inspection
of high-frequency signal components.
sweep magnifier In an oscilloscope, a circuit for
achieving sweep magnification.
sweep oscillator See SWEEP GENERATOR.
sweep period The duration, in seconds, of one
complete cycle of sweep signal in an oscilloscope.
It is equal to the reciprocal of the SWEEP FRE-
QUENCY.
sweep signal The (usually linear, sawtooth) signal
used to sweep the beam of an oscilloscope tube.
Also see SWEEP, 1, 2.
sweep-signal generator A signal generator that
supplies a signal whose frequency varies automatically
and periodically throughout a given band.
Frequency
f max
f min
Time
sweep-signal generator
sweep test A method of testing the attenuationvs.-frequency
characteristics of a selective circuit,
using a radio-frequency sweep generator.
sweep time The actual time required for a single
sweep by a deflecting signal; t = 1/f, where t is
sweep time in seconds, and f is sweep frequency
in hertz.
sweep voltage The peak voltage amplitude of the
sweep signal.
SWG Abbreviation of standard wire gauge.
swing The maximum change exhibited by a varying
quantity (e.g., amplitude swing and frequency
swing).