Electronic terms, glossary of electronic terms, electronic terms
starting from alphabet S, Collection of Electronic Definitions, electronic
Acronyms and terms related to electronic industry
SMB / SMC -
Types of small coaxial
signal connectors typically used in high frequency applications. SMC threads
to the mating connector while the SMB "snaps" to the mating connector
saturation
Condition in which a further increase
in one variable produces no further increase in the resultant effect. In a
bipolar junction transistor, the condition when the emitter to collector
voltage is less than the emitter to base voltage. This condition puts
forward bias on the base to collector junction.
saw tooth wave
Repeating waveform that rises from
zero to maximum value linearly drops back to zero and repeats. A ramp
waveform.
scale
Set of markings used for measurement.
schematic diagram
Illustration of an electrical or
electronic circuit with the components represented by their symbols.
Schmitt trigger
Circuit to convert a given waveform
to a square wave output.
Schottky diode
High speed diode that has very little
junction capacitance. Also known as a "hot-carrier diode" or a
"surface-barrier diode."
scientific notation
Numbers entered as a number from one
to ten multiplied by a power of ten. Example: 8765 = 8.765 × 103.
secondary
Output winding of a transformer.
Winding that is connected to a load.
secondary cell
Electrolytic cell used to store
electricity. Once discharged may be restored by recharging by putting
current through the cell in the direction opposite to that of discharge
current.
selectivity
Charistic of a circuit to
discriminate between wanted and unwanted signals.
self biasing
Gate bias for a field effect
transistor in which source current through a resistor produces the voltage
for gate to source bias.
self inductance
Property that causes a counter
electromotive force to be produced in a conductor when the magnetic field
expands or collapses with a change of current.
semiconductor
An element which is neither a good
conductor or a good insulator, but rather lies somewhere between the two.
Characterized by a valence shell containing four electrons. Silicon,
germanium and carbon are the semiconductors most frequently used in
electronics.
series circuit
Circuit in which the components are
connected end to end so that current has only one path to follow through the
circuit.
series parallel network
Network that contains components
connected in both series and parallel.
series resonance
Condition that occurs in a series LC
circuit at the frequency where inductive reactance equals capacitive
reactance. Impedance is minimum, current is maximum limited only by
resistance in the circuit.
seven segment display
Device made of several light emitting
diodes arranged in a numeric or alphanumeric pattern. By lighting selected
segments numeric or alphabet characters can be displayed.
shells or bands
Orbital path containing a group of
electrons having a common energy level.
shield
Metal grounded cover used to protect
a wire, component or piece of equipment from stray magnetic and/or electric
fields.
short circuit
Also called a short. Low resistance
connection between two points in a circuit typically causing excessive
current.
shunt resistor
Resistor connected in parallel or in
shunt with another component or circuit.
signal
Electrical quantity that conveys
information.
signal to noise ratio
Ratio of the magnitude of the signal
to the magnitude of noise usually expressed in decibels.
silicon
(Si) Non metallic element (atomic
number 14) used in pure form as a semiconductor.
silicon-controlled rectifier
(SCR) Three terminal active device
that acts as a gated diode. The gate terminal is used to turn the device on
allowing current to pass from cathode to anode.
silicon controlled switch
An SCR with an added terminal called
an anode gate. A positive pulse either at the anode gate or the cathode gate
will turn the device on.
silicon dioxide
Glass like material used as the gate
insulating material in a MOSFET.
silicon transistor
A bipolar junction transistor using
silicon as the semi conducting material.
silver
(Ag) Precious metal that does not
easily corrode and is more conductive than copper.
silver mica capacitor
Mica capacitor with silver deposited
directly onto the mica sheets instead of using conductive metal foil.
silver solder
Solder composed of silver, copper and
zinc. Has a melting point lower than pure silver, but higher than lead-tin
solder.
simplex
Communication in only one direction
at a time. Example: FAX.
simulcast
Broadcasting a program simultaneously
in two different forms, for example a program broadcast in both AM and FM.
sine
Sine of an angle of a right angle
triangle is equal to the opposite side divided by the hypotenuse.
sine wave
Wave whose amplitude is the sine of a
linear function of time. It is plotted on a graph that plots amplitude
against time or radial degrees relative to the angular rotation of an
alternator.
single in-line package
Package containing several electronic
components (generally resistors) with a single row of connecting pins.
single pole double throw
(SPDT) Three terminal switch in which
one terminal can be connected to either one of the other terminals.
single pole single throw
(SPST) Two terminal switch or relay
that can open or close one circuit.
single sideband
(SSB) AM radio communication
technique in which the transmitter suppresses one sideband and therefore
transmits only a single sideband.
single throw switch
Switch containing only one set of
contacts which can be either opened or closed.
sink
Device such as a load that consumes
power or conducts away heat.
sintering
Process of bonding either a metal or
powder by cold pressing it into a desired shape and then heating to form a
strong cohesive body.
sinusoidal
Varying in proportion to the sine of
an angle or time function. AC voltage in which the instantaneous value is
equal to the sine of the phase angle times the peak value.
SIP
Abbreviation for "single in-line
package."
skin effect
Tendency of high-frequency (rf)
currents to flow near the surface layer of a conductor.
slew rate
The maximum rate at which the output
voltage of an op-amp can change.
slide switch
Switch having a sliding button, bar
or knob.
slow acting relay
Slow operating relay that when
energized may not pull up the armature for several seconds.
slow-blow fuse
Fust that can withstand a heavy
current (up to ten times its rated value) for a small period of time before
it opens.
snap switch
Switch containing a spring under
tension or compression that causes the contacts to come together suddenly
when activated.
SNR
Abbreviation for "signal to noise
ratio."
soft magnetic material
Ferromagnetic material that is easily
demagnetized.
software
Program of instructions that directs
the operation of a computer.
solar cell
Photovoltaic cell that converts light
into electric energy. Especially useful as a power source for space
vehicles.
solder
Metallic alloy used to join two metal
surfaces.
soldering
Process of joining two metallic
surfaces to make an electrical contact by melting solder (usually tin and
lead) across them.
soldering iron
Tool with an internal heating element
used to heat surfaces being soldered to the point where the solder becomes
molten.
solenoid
An air core coil. Equipped with a
movable iron core the solenoid will produce motion. As a result of current
through the coil the iron core is pulled into the center of the winding.
When the coil is deenergized, a spring pulls the movable core away from the
center of the winding. Mechanical devices connected to the movable core are
made to move as a result of current through the coil. Example: Electric door
locks on some automobiles.
solid conductor
Conductor having a single solid wire
instead of strands of fine wire twisted together.
solid state
Pertaining to circuits where signals
pass through solid semiconductor material such as transistors and diodes as
opposed to vacuum tubes where signals pass through a vacuum.
sonar
Acronym for "sound navigation and
ranging." A system using reflected sound waves to determine the position of
some target.
sonic
Pertaining to sound.
sound wave
Pressure waves propagated through air
or other plastic media. Sound waves are generally audible to the human ear
if the frequency is between approximately 20 and 20,000 vibrations per
second. (hertz)
source
Device that provides signal power or
energy to a load.
source follower
FET amplifier in which signal is
applied between gate and drain with output taken between source and drain.
Also called "common drain."
source impedance
Impedance through which output
current is taken from a source.
south pole
Pole of a magnet into which magnetic
lines of force are assumed to enter.
spark
Momentary discharge of electrical
energy due to ionization of air or other dielectric material separating two
charges.
SPDT
Single pole double throw.
speaker
Also called "loudspeaker." Transducer
that converts electrical energy into mechanical energy at audio frequencies.
spectrum
Arrangement or display of light or
other forms of electromagnetic radiation separated according to wavelength,
energy or some other property.
spectrum analyzer
Instrument used to display the
frequency domain of a waveform plotting amplitude against frequency.
speed-up capacitor
Capacitor added to the base circuit
of a BJT switching circuit to improve the switching time of the device.
SPST
Abbreviation for "single pole single
throw."
square wave
Wave that alternates between two
fixed values for an equal amount of time.
static
Crackling noise heard on AM radio
receivers. Caused by electric storms or electric devices.
static electricity
Stationary electric charges.
static reverse current
Reverse current through a zener diode
when the reverse voltage across the diode is less than the zener voltage
rating of the device.
stator
Stationary part of some rotary device
such as a variable capacitor.
step-down transformer
Transformer in which the output AC
voltage is less than the input AC voltage.
step-up transformer
Transformer in which the output AC
voltage is greater than the input AC voltage.
stereo sound
System in which reproduced sound is
delivered through two or more channels to give a sense of direction to the
source.
stop band
Range of frequencies outside the pass
band of a tuned amplifier.
storage time
In a BJT switching circuit, it is the
time required for collector current to drop from 100% to 90% of its maximum
value.
stranded conductor
Conductor composed of a group of
strands of wire twisted together.
stray capacitance
Undesirable capacitance that exists
between two conductors such as two leads or one lead and a metal chassis.
subassembly
Components contained in a unit for
convenience in assembling or servicing equipment.
subatomic
Particles such as electrons, protons
and neutrons that are smaller than atoms.
substrate
Mechanical insulating support upon
which a device is fabricated.
summing amplifier
An op-amp circuit whose output is
proportional to the sum of its instantaneous voltages.
superconductor
Metal such as lead or niobium that,
when cooled to within a few degrees of absolute zero, can conduct current
with no resistance.
super heterodyne receiver
Radio receiver that converts all
radio frequencies to a fixed intermediate frequency to maximize gain and
bandwidth before demodulation.
super high frequency
(SHF) Frequency band between 3 GHz
and 30 GHz. So designated by Federal Communications Commission (FCC).
superposition theorem
Theorem designed to simplify networks
containing two or more sources. It states that in a network containing more
than one source, the current at any one point is equal to the algebraic sum
of the currents produced by each source acting separately.
supply voltage
Voltage provided by a power source.
surface-barrier diode
(Schottky diode)High speed diode that
has very little junction capacitance. Also known as a "hot-carrier diode."
surface leakage current
Diode reverse current that passes
along the surface of the semiconductor materials.
surge current
High charging current that flows into
a power supply filter capacitor as the power is first turned on.
sweep generator
Test instrument designed to produce a
voltage that continuously varies in frequency over a band of frequencies.
Used as a source to display frequency response of a circuit on an
oscilloscope.
switch
Electrical device having two states,
on (closed) or off (open). Ideally having zero impedance when closed and
infinite impedance when open.
switching transistor
transistor designed to change rapidly
between saturation and cut-off.
synchronization
Also called sync. Precise matching of
two waves or functions.
synchronous
Two or more signals in step or in
phase.
sync pulse
Pulse used as a reference for
synchronization.
system
Combination of several pieces of
equipment to perform in a particular manner
Software Development Kit.
This is a kit of software
SMA - A small type of threaded
coaxial signal connector typically used in higher frequency applications.
This connector is typically usable to 26GHz.
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