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SAMPLING - The act of periodically collecting or sending information. A microcomputer samples input from various sensors in the process of controlling a system.
SCHEMATIC DIAGRAM - Symbolic representation of an electric circuit or vacuumhose circuit.

SEALED-BEAM - Headlight design incorporating filaments, reflector, and a lens in a unit with no separate bulb.


SECONDARY - (1) A high-voltage circuit or part of a circuit. (2) The output coil of a transformer.


SECONDARY CIRCUIT - The high voltage part of the ignition system which extends from the center tower of the coil all the way down to and across the spark plug gap.

SECONDARY INSULATION (SPARK PLUG WIRE):

SECONDARY INSULATION - The material that contains the spark from the time it leaves the center tower of the coil to the time it reaches the insulated electrode of the spark plug.
SECONDARY RESISTANCE - The resistance encountered by electricity as it travels on its route from the center tower of the coil to the ground electrode of the spark plug.


SECONDARY WINDING - See "Secondary Circuit."

SEMICONDUCTOR - General term for transistors, integrated circuits, and other electronic devices made of materials, such as silicone, that conduct electricity poorly.

SENSOR - Used as inputs to the ECA, a device that measures a condition and converts it into some kind of electrical signal.
SERIES - An electrical connection in which two or more circuits, batteries or components are connected negative to positive. The opposite of "parallel."

SERVO - In a speed control system, a vacuum operated device controlled by the amplifier responsible for changing the throttle plate settings in relationship to engine speed. The servo contains solenoid valves for controlling vacuum to the diaphragm and a throttle position sensor (servo in IVSC system does not contain throttle position sensor).

SET/ACCEL - In a speed control system, a driver control button that is responsible for setting a speed. It can also be used to raise the speed by holding it down until the desired speed is reached.

SHIFT INDICATOR LIGHT (SIL) - A system primarily controlled by engine speed and manifold vacuum which provides a visual indication to the driver of when to shift to the next higher gear to obtain fuel economy.


SHORT CIRCUIT - Defect in an electric circuit in which electricity flows directly from one conductor to another rather than through the intended circuit.

SHUNT - A conductor joining two points in a circuit so as to form a parallel circuit through which a portion of the current may pass in order to regulate the amount of current flowing in the main circuit.

SHUNT CIRCUIT - A minor side circuit that parallels and feeds off a main circuit.


SIGNAL - A voltage condition that transmits specific information in an electronic system.

SIGNAL PROCESSING - A general term used for conditioning input signals. It covers many functions such as A/D converting, amplifying, counting, etc. It describes what happens to input signals from the sensor on their way to the microprocessor.


SINE-WAVE - A voltage signal generated by a coil of wire, a magnetic field and movement between them.
SLIP RING - A circular conductor on a rotor or armature that contacts brushes. Electricity flows from the brushes to the slip ring, thus allowing current to pass from a stationary part to a rotating part.


SLOW CHARGE - The preferred method of administering a charge to a battery where current is applied over a long period of time and at a low rate.

SOLENOID - A wire coil with a moveable core which changes position by means of electromagnetism when current flows through the coil. Sometimes synonymous with "relay."

SOLENOID RELAY - A switching component in the starter motor circuit. Light current operates the solenoid, which closes the contacts carrying the heavy current to the starter motor.

SOLENOID SWITCH - A switch operated by a solenoid.


SOLENOID VACUUM SWITCH - Any one of a variety of engine control devices that combine a solenoid switch and a vacuum valve. The solenoid opens or closes a valve in a vacuum line, usually as part of a pollution-control system.


SOLID STATE - General term for transistors and related electronic components that are replacing vacuum tubes.


SOLID STATE IGNITION (SSI) - The ignition systems that used a transistor to switch the coil. One used breaker points to switch on the transistor, the other used the magnetic pickup coil. Both of these systems precede the Duraspark systems, but the one that used the pickup coil is the same.

SPARK ADVANCE - Causing the ignition spark to occur earlier.

SPARK GAP - The space between the spark plugs center electrode and ground electrode.
SPARK LINE - The pattern that represents the time during which the air/fuel mixture is being burned within the combustion chamber.


SPARK PLUG - Electrical component that produces a spark to ignite the air/fuel mixture in the cylinders.


SPARK RETARD - Causing less spark advance to be added, resulting in an ignition spark introduced later.


SPLICE - The joining of two or more conductors at a single point by crimping, soldering or brazing.


SQUARE-WAVE - A digital on-off type of signal that has a very fast rise and fall.


STARTER - The electric motor and drive mechanism used to start an engine.


STOPLAMP SWITCH - Switch responsible for disabling the speed control system when the brakes are applied. Also responsible for operating the stoplamps when the brake pedal is depressed.

STORAGE CELLS - A cell which stores potential for electricity in the form of chemicals. Once discharged it can be recharged by forcing current through it in the opposite direction. These cells, when placed in series, form a storage battery.


STRATEGY - The programming of the ECA determining how it reacts under certain conditions. Some currently used strategies are Failure Mode Effects Management (FMEM), Idle, Lean Cruise, etc.


SWITCH - A device used to open, close or redirect the current in an electrical circuit.