Electronics Glossary Propagation Time: Time required for a wave to travel between two points on a transmission line. Protocol: A set of rules for communicating. Proximity Effect: Nonuniform current distribution over the cross-section of a conductor caused by the variation of the current in a neighboring conductor. Pull Box: A device to access a raceway used to facilitate placing of wire or cables. Pull Cord/Pull Wire: Cord or wire placed within a raceway and used to pull wire and cable through the raceway. Pull Strength: See Pull Tension. Pull Tension: The maximum pulling force that can be safely applied to a cable without damage. Pulling Eye: A device used to pull cable into or from a duct. Pulse: Energy which changes abruptly from an intensity to another. May be light energy or electrical energy. Pulse Cable: A type of coaxial cable constructed to transmit repeated high-voltage pulses without degradation. Polyvinyl Chloride (PVC): A general-purpose thermoplastic widely used for wire and cable insulations and jackets. Quad: A series of four separately insulated conductors, generally twisted together in pairs. Also, a series-parallel combination of transistors with increased reliability because failure of one transistor will not disable the entire circuit. Quadders: Three-bay machines which can twist four wires together and cable braided and shielded wires with varying lay lengths. Raceway: Any channel designed for holding wires or cables, e.g. conduit, electrical metallic tubing, sleeves, slots, underfloor raceways, cellular floors, surface raceways, lighting fixture raceways, wireways, cable troughs, busways, auxiliary gutters and ventilated flexible cableways. Synonym: Pathway. Rack: See: Cable Rack. Radio Frequency: The frequencies in the electromagnetic spectrum that are used for radio communications. Random Winding: A winding in rotating equipment wherein the wires do not lie in an even pattern. Reinforced Sheath: The outermost covering of a cable that has cable sheath constructed in layers with the addition of a reinforcing material, usually a braided fiber, molded in place between layers. Remanence: The magnetic induction that remains in a magnetic circuit after the removal of an applied magnetomotive force. Repeater: A device which consists of a transmitter and a receiver or transmitter, used to regenerate a signal to increase the system transmission length. Resistance: A measure of the difficulty in moving electrical current through a medium when voltage is applied. It is measured in Ω. Resistive Conductor: A conductor with high electric resistance. Segmental Conductor: A stranded conductor consisting of three or more stranded conducting elements, each element having approximately the shape of the sector of a circle, assembled to give a substantially circular cross-section. Selenium Cure: Process used to cure neoprene and rubber jacketed wires and cables. Self-Extinguishing: Characteristic of a material whose flame is extinguished after the igniting flame source is removed. Semi-Conducting Jacket: A jacket having a sufficiently low resistance so that its outer surface can be kept at substantially ground potential. Retractile Cord: A cord having specially treated insulation or jacket so that it will retract. Return Wire: A ground wire or the negative wire in a direct-current circuit. Ribbon Cable: A flat cable of individually insulated conductors lying parallel and held together by means of adhesive or woven textile yarn. Ridge Marker: One or more ridges running laterally along the outer surface of a plastic- insulated wire for purposes of identification. Rigid Bay: Cabling equipment that maintains component sequence, and can produce cables with distinct layers. Rigid Coaxial Cable: Nonflexible coaxial cable, usually a metal tube armored coaxial cable. Ring Tongue: A solderless terminal that connects wire to a stud. Ringing Out: Locating or identifying specific conductive paths by passing current through selected conductors. Rip-Cord: 1.) Two or more insulated conductors in a parallel configuration which may be separated to leave the insulation of each conductor intact. 2.) A small filament cord used to rip through the outer cable sheath. RoHS (Restriction on Hazardous Substances): European Union directive that restricts use of heavy metal substances. Reactance: The opposition offered to the flow of alternating current by inductance or capacitance of a compound or circuit. Red Plaque: A powdery, brown-red growth found on silvercoated copper conductors and shield braids. Redraw: The consecutive drawing of wire through a series of dies to reach a desired wire size. Rope Concentric: A group of standard conductors assembled in a concentric manner. Rope Unilay: A group of stranded conductors assembled in a unilay manner. Reducing Joint: A joint between two lengths of cable where the conductors are not the same size. Semi-Rigid: A cable containing a flexible inner core and a relatively inflexible sheathing. Semi-Solid: An insulation cross-section having a partially open space between the conductor and the insulation perimeter. Separator: A layer of insulating material which is placed between a conductor and its dielectric between a cable jacket and the components it covers, or between various components of a multiple-conductor cable. Series Circuit: A circuit in which the components are arranged end to end to form a single path for current. Technical Information Rope Lay Conductor: A conductor composed of a central core surrounded by one or more layers of helically laid groups of wires. Reel: A revolvable flanged device made of wood or metal, used for winding flexible metal wire or cable. Reflection: (fiber optic) Change in direction of a light wave or ray. Reflection Loss: The part of a signal which is lost due to reflection of power at a line discontinuity. Refraction: (fiber optic) The bending of lightwaves or rays as they go from one material to another due to the difference in velocities in the materials. Routers: A device that determines how to forward a packet toward its destination, based on tables that indicate the costs, congestion status and other factors associated with possible routes. Also called a level 3 relay or an intermediate system. Rubber (Wire Insulation): Term used to describe wire insulations made of thermosetting elastomers; occurs naturally or may be made synthetically. Rulan®: DuPont’s trade name for their flame- retardant polyethylene insulating material. Round Wire Shields: Shields constructed from bare, tinned or silver-plated copper wire that include braided, spiral and reverse spiral. Serve: A filament or group of filaments such as fibers or wires, wound around a central core. Serving: A wrapping applied over the core of a cable or over a wire. Sheath: See Cable Sheath. Shield: In cables, a metallic layer placed around a conductor or group of conductors to prevent electrostatic or electromagnetic interference between the enclosed wires or external fields. Shield Coverage: Amount of outer cable covered by the shielding material. Shield Effectiveness: The ability of a shield to screen out undesirable signals. Shielded Line: A transmission line whose elements confine propagated radio waves to an essentially finite space inside a tabular conducting surface called the sheath, thus preventing the line from radiating radio waves. Shielded-Type Cable: A cable in which the surface of the insulation is at ground potential. Shunt Wire: A conductor joining two parts of an electric circuit to divert part of the current. Signal: A current used to convey information, either digital, analog, audio or video. Silicone: A material made from silicon and oxygen. Can be in thermosetting elastomer or liquid form. The thermosetting elastomer form is noted for high heat resistance. Screen: A shield placed over the entire core. Secondary Insulation: A nonconductive material that protects the conductor against abrasion and provides a second electrical barrier. Silicone Treating: A silicone liquid treatment applied to insulated conductors to allow for easy jacket stripping. Sine Wave: A wave that can be expressed as the sine of a linear function of time, or space or both. Single-ended: Unbalanced, such as grounding one side of a circuit or transmission line. Single-Faced Tape: Fabric tape finished on one side with a rubber or synthetic compound. Singlemode Fiber: A fiber wave guide in which only one mode will propagate. The fiber has a very small core diameter of approximately 8mm. It permits signal transmission at extremely high bandwidths and is generally used with laser diodes. 188