18WuD2x

silver-oxide cell • single cotton enameled wire 631
generated potential difference under no-load conditions
is 1.5 volts, with a high ratio of stored energy
per unit mass. The cell has a flat discharge
curve; the voltage remains essentially constant
until the charge is almost depleted, and then the
voltage drops rapidly.
silver solder A solder consisting of an alloy of silver,
copper, and zinc. It has a comparatively high
melting temperature. Also see HARD SOLDER.
silverstat A multiconductor device used to adjust
the balance of a resistance or reactance bridge.
similar decimals Two or more decimal numbers
that have the same number of digits to the right
of the radix point (e.g., 3.14 and 6.39, or 1.234
and 1.000).
simple quad A combination of two parallel paths—
each containing two elements in series.
simple tone A pure sine-wave tone (i.e., one having
negligible harmonic content).
simplex channel An information channel for unidirectional
transmission.
simplex system 1. In data communications, a system
that transmits data in only one direction.
Compare FULL DUPLEX SYSTEM and HALF DU-
PLEX SYSTEM. 2. In voice communications via
radio, a direct path over a single channel, used
alternately for transmitting and receiving at each
station.
simplex telegraphy Wire telegraphy in which only
one message at a time can be sent over a line.
simplification of circuits See CIRCUIT SIMPLIFI-
CATION.
simulation 1. Imitation of the performance of a
process, device, or system. 2. The use of a mathematical
model to represent a physical process,
device, or system. 3. The use of a computer,
sometimes with virtual reality hardware and software,
to mimic a real-life situation.
simulator
1. A software or hardware system capable
of simulation (see SIMULATION, 2). 2. A computer
program whose implementation allows
programs written for one computer to be compatible
with another computer. 3. A system of equipment
for simulation (see SIMULATION, 1).
simulcast
1. To broadcast a program over two or
more different channels at the same time. 2. To
broadcast a program over two or more different
types of mode, for example, television and radio,
at the same time. 3. A program broadcast over
two or more channels or modes at the same
time.
simultaneous access See PARALLEL ACCESS.
simultaneous broadcasting See SIMULTANEOUS
TRANSMISSION.
simultaneous computer See PARALLEL COM-
PUTER.
simultaneous transmission The transmission of
the same information in two or more channels, or
by means of two or more processes, at the same
time.
sin Abbreviation of SINE.
sin –1 Symbols for the inverse of the sine function,
also called the arc sine.
sine Abbreviation, sin. The trigonometric function
a/c, the ratio of the opposite side of a right triangle
to the hypotenuse.
SINAD See SIGNAL-TO-NOISE-AND-DISTORTION
RATIO.
sine galvanometer A galvanometer in which the
sine of the angle of deflection is proportional to
the current. Compare TANGENT GALVANOME-
TER.
sine law The variation in radiation intensity in any
direction from a linear source is proportional to
the sine of the angle between the axis of the
source and the direction of interest.
sine potentiometer A POTENTIOMETER whose
output is proportional to the sine of the angle
through which the shaft has rotated.
sine wave A periodic wave that can be represented
by a sine curve (i.e., its amplitude is directly proportional
to the sine of a linear quantity, such as
displacement or time). Compare COSINE WAVE.
0°
90°
180° 360°
270°
sine wave
singing Audible oscillation in a circuit or device,
such as the low-level buzz emanating from the filament
of a lamp dimmed with a phase-control
circuit.
single-address coding In computer programming,
the use of instruction words that contain the address
for the location of the data to be operated
on, and no other addresses.
single-board computer Abbreviation, SBC. A computer
built entirely on one circuit board.
single-button microphone A carbon microphone
having only one button attached to the diaphragm.
Also see BUTTON MICROPHONE.
single-channel codec A form of CODEC intended
for operation on a single signal source, rather
than in a multiplexed system.
single-chip codec An integrated circuit contained
entirely on one chip and in one package that can
accomplish all CODEC functions. It can be a single-channel
device or multiplexed.
single-cotton-covered wire Wire insulated with
one layer of cotton.
single cotton enameled wire Wire insulated with
one layer of cotton on top of an enamel coating.