Dictionary of Electrical and Electronic Terms
"A"
"B"
"C",
"D",
"E",
"F",
"G",
"H",
"I",
"J",
"K",
"L",
"M",
"N",
"O",
"P",
"Q",
"R",
"S",
"T",
"U",
"V",
"W",
"X",
"Y",
"Z"
"S" to "Sec",
"Sel" to "Series pa", "Series pe" to "Shr",
"Shu" to "Sil", "Sim" to "Skip",
"Sky" to "Spe",
"Spi" to "Sta",
"Ste" to "Stz", "Su", "Sw",
"Sx" to "Sz"
Subassembly. Consists of two or more parts that form a portion of an assembly or a unit.
Subcarrier. A carrier that was used to generate a modulated wave, and that wave is then used in the generation of another modulated wave.
Subharmonic. An exact submultiple of the fundamental frequency. Even sub-harmonics are one-half,
one-quarter, and so on. Odd subharmonics are one-third, one-fifth, and so on of the fundamental
frequency.
Subroutine. A section of code that is entered from a main routine, is executed, and than passes control back to the main routine or section of code.
Substrate. The supporting material upon or within which the elements of a microcircuit or integrated circuit are fabricated or attached. Mounting surface for integrated circuits. May be semiconductor or insulator material
depending on type of IC. The material underneath the magnetic coating of a hard disk.
Sudden Ionospheric Disturbance. An irregular ionospheric disturbance that can totally blank
out High-Frequency [HF] radio communications.
Summing Amplifier. A circuit that performs both a summing function and amplification. A Summing Op-Amp circuit. The summing circuit to the right may also be a Summing Amplifier depending on the value of Rf and Rn [the input resistors].
Summing Circuit. See Summing Network.
Summing Network. A combination of two or more parallel resistors used in servo-systems as an
error detector. The output of the network is the algebraic sum of the inputs. The circuit example shows an Op Amp summing circuit [R1 to Rn].
Sum-of-Products. A product term of several product terms logically added together.
Sum Term. A single term or the sum of several variables.
Sunlight Readable. A display with an output which is visible under direct sunlight conditions when illuminated
and hidden when not illuminated.
Superheterodyne: The process of translating a high frequency to a lower frequency.
Superheterodyne Receiver. A type of receiver that uses a mixer to convert an incoming RF signal into an
IF signal for amplification. Read more about the Superheterodyne Receiver.
Superhigh Frequency. The band of frequencies from 3 gigahertz to 30 gigahertz.
Super-Multiplexing. A method of increasing channel capacity by multiplexing multi-levels.
Suppressed Carrier Transmission. Radio transmission in which the carrier is not transmitted, only one or both or both of the sidebands are transmitted.
Suppression. The process of eliminating an undesired portion of a signal.
Surface leakage. Undesired current flow along the surface of a material rather than through the bulk of the material.
Surface Wave. Radio waves that travel along the contours of the earth, thereby being highly attenuated.
Surge. The sudden change in voltage or current in a circuit. Surge current is a sudden change in line current to a user equipment that occurs during start-up or as a result of a change to
the operating mode.
Surge Resistor. A small value resistor placed in series with a diode to limit the forward current through the diode, so the peak current rating of the diode is not exceeded.
Surge Suppressor. A 2-terminal device that will conduct in either direction once a specific voltage level is reached. A Transient Voltage Suppressor [TVS]. Two back-to-back diodes. A device used to protect equipment from a voltage spikes. Also refer to AC Surge Suppressor Devices, and UPS gear.
Surge Voltage. A large increase in voltage. See surge.
Susceptance. [B] The imaginary part of admittance and measured in siemens.
Suspension Insulator. A glass insulator used on power line suspension cables which supports the power cable. A graphic of different size glass suspension insulators is shown to the right.
