Electronic Engineering Dictionary

Slewing. Rotating a directional antenna or transducer rapidly about one or more axes.

Slew Rate. The rate of change of the out put of an integrated circuit, as it switches. A separate page covers this topic in greater detail; Slew Rate definition. The internally limited rate of change in the output voltage with a larger amplitude step function applied to the input [analog IC]. The time rate of change of the closed-loop amplifier output voltage for a step signal input. Normally, slew rate is measured using the largest input voltage step for which the amplifier performance remains linear with feedback adjusted for unity gain.

Slide Switch. A switch designed to be actuated by the sliding of a button, bar, or knob. Related listing; Slide Switch Vendors.

Slip. The difference between rotor speed and synchronous speed in an ac induction motor. Related topic; Electric Motor Vendors.

Slip Rings. Contacts that are mounted on the shaft of a motor or generator to which the rotor windings are connected and against which the brushes ride. Devices for making electric connections between stationary and rotating contacts.

Slope Detector. A tank circuit tuned to a frequency, either slightly above or below an FM carrier frequency, that is used to detect intelligence. The slope detector works on the audio frequency changes in an FM signal providing a greater amplitude to higher frequencies than lower ones [the slope] the amplitude changes than become an amplitude modulated signal which could than be converted back to audio.

Slot. Narrow opening in a waveguide wall used to couple energy in or out of the waveguide. Also called an aperture or a window. A protocol data unit (PDU) that consists of user information in a distributed-queue dual-bus.

Slotted-Ring Network. A ring network that allows unidirectional data transmission between data stations by transferring data in predefined slots in the transmission stream over one transmission medium such that the data return to the originating station.

SMA. A style of threaded coaxial connector. SMA Definition [located in the Radar dictionary]

Small Signal. A signal shall be considered small if doubling its magnitude does not produce a change in the parameter being measured that is greater than the specified accuracy of the measurement [example; Small signal diode, small signal transistor].

Snap-Acting. Changing position quickly with the aid of a spring. Related topic; Snap-in Rocker Switches.

Socket. A component permanently attached to a board or some other fixture which allows another component to be installed or removed with out any tools. A component used as a mounting platform for another component using a temporary compression fit, as in an IC socket. Also refer to IC Socket Vendors.

Socket Adapter. An IC socket that adapts one pin configuration to another. For example; A socket adapter could accept a surface mount IC, but plug into a through-hole pattern, or accept one version of a pin configuration and translate that into an alternate pin out.

Soft-Error. A data error which can be corrected by attempting to re-read or re-writing the data.

Solder-Cup. A type of connector pin with a cup on one end to accept a wire and solder as a connection point. [graphic right side]

Solder Hook. A type of terminal shaped like a hook. The component may have any number of hook shaped terminals. A number of components might use a solder hook as a terminal option, to include relays, transformers and capacitors.

Solder Cup Pin

Solder Sleeve. A heat-shrinkable solder termination device with meltable sealing performs at ends.

Solderless Terminal. A terminal that is used for wire attachment other than with solder, as in a Wire Wrap Terminals, or crimp terminal. A solderless terminal is a terminal that has at least one side that uses a wire connection that does not require solder to make the mechanical and electrical connection. Solderless Terminals are crimp on parts that do not require solder as a connection, as with Terminal Lugs. In general there are two main types; a Permanent Splice which is used to crimp two wires together, and a Lug type terminal, in which a wire is crimped at one end and uses a lug as the attachment on the other end. Although some terminations may be the Quick Disconnect type. Solderless terminals may be insulated or un-insulated.

Manufacturers of Connectors.

Solenoid. An electro-magnetic device that changes electrical energy into mechanical motion; based upon the attraction of a movable iron plunger to the core of an electromagnet. See Relay Manufacturers.

Solid-State Device. An electronic device that operates by the movement of elections within a solid piece of semiconductor material.

Solid State Relay. A component that uses a semiconductor device to act as the contacts of a relay. Except for a hybrid component, normally there are no movable parts in a solid state relay. The opening and closing of what would be a relay contact is performed by the on and off action of a semiconductor switch. Also see Solid-State Relay Manufacturers

Solid-State Lighting. SSL is an umbrella term encompassing both light-emitting diodes (LEDs) and organic light emitting diodes (OLEDs). Read more about SSL.

Sonic. Pertaining to sounds capable of being heard by the human ear.

Source. The object that produces the waves or disturbance. The name given to them end of a two-wire transmission line that is connected to a source. The device which furnishes the electrical energy used by a load. An electrode on an FET.

Source Current. An integrated circuit sources current when current is flowing from the IC into another device [Load]. Source-ing current is considered to be positive current flow from the ICs prospective. Source current is the opposite to Sink Current.

Source Follower. The FET version of an Emitter follower.

Source Impedance. The impedance presented to the input terminals of another circuit or component.

Space. Absence of an RF signal in cw keying. Key-open condition or lack of data in communications systems. Also a period of no signal.

Space Charge. An electrical charge distributed throughout a volume or space.

Space Diversity. Reception of radio waves by two or more antennas spaced some distance apart.

Space Wave. Radio waves that travel directly from the transmitter to the receiver and remain in the troposphere.

Spark-Gap Modulator. A modulator that consists of a circuit for storing energy, a circuit for rapidly discharging the storage circuit (spark gap), a pulse transformer, and a power source.

Speaker. [Loudspeaker] A device that radiates acoustic energy into the air. An electroacoustic transducer that converts an electrical signal into sound. More detail on Speaker Manufacturers The graphic shows a 5.1 speaker system.

Speaker System

Specific Gravity. The ratio between the density of a substance and that of pure water at a given temperature.

Specific Resistance. The resistance measured in ohms of a unit volume of a substance to the flow of electric current. (The unit volume used is generally the circular mil-foot.)

Spectrum. The entire range of electromagnetic waves arranged in order of their frequencies. The range of frequencies considered in a system. The range of electromagnetic radio frequencies used in the transmission of sound, data and television [TV].

Spectrum Analysis. The display of electromagnetic energy arranged according to wavelength or frequency.

Spectrum Analyzer. A test instrument that provides a visual display of the frequency distribution of an RF signal such as a transmitter output. Refer here for Manufacturers of Spectrum Analyzers.

Spectrum Analyzer

Speed-up Capacitor. A capacitor in parallel with another component, which initially acts as a 'short'. Also refer to the dictionary of Capacitor Terms.