Electronics Glossary Tinsel Wire: A low-voltage stranded wire, with each strand a very thin conductor ribbon spirally wrapped around a textile yarn. Topcoat: Bare (untinned) copper wire, stranded then coated with pure tin. Topology: The physical or logical arrangement of a telecommunications system. Tracer: A means of identifying polarity. Transducer: A device for converting mechanical energy to electrical energy. Transfer Impedance: The ratio of the source voltage of the wires inside the cable to the shield current of the cable or connectorized cable assembly. Transition Point: A location in the horizontal cabling where flat undercarpet cable connects to round cable. Transmission Cable: Two or more transmission lines. See Transmission Line. Twin Cable: A pair of insulated conductors twisted, sheathed or held together mechanically and not identifiable from each other in a common covering. Twin Coaxial: A configuration containing two separate, complete coaxial cables laid parallel or twisted around each other in one complex. Twin Line: A transmission line which has a solid insulating material, in which the two conductors are placed in parallel to each other. Twinner: A device for twisting together two conductors. Transmission: Transfer of electric energy from one location to another through conductors or by radiation or induction fields. Transmission Line: An arrangement of two or more conductors or a wave guide used to transfer signal energy from one location to another. Transmission Loss: The decrease or loss in power during transmission of energy from one point to another. Usually expressed in decibels. Transmission Media: The various types of wire and optical fiber cable used for transmitting voice or data signals. Typically, wire cable includes twisted pair, coaxial and twinaxial. Optical fiber cable includes single, dual, quad, stranded and ribbon (Al). Transparent: (fiber optic) Transmitting rays of light so that objects can be seen through the material. Twisted Pairs: A cable composed of two small insulated conductors twisted together without a common covering. Unbalanced Line: A transmission line in which voltages on the two conductors are unequal with respect to ground. Unidirectional Concentric Stranding: A stranding where each successive layer has a different lay length, thereby retaining a circular form without migration of strands from one layer to another. Unidirectional Stranding: A term denoting that in a stranded conductor, all layers have the same direction of lay. Unilay Strand: A conductor constructed with a central core surrounded by more than one layer of helically-laid wires, with all layers having a common length and direction of lay. Transmitter: The electronic package that injects an electrical signal or light signal over the transmission medium. Transposition: Interchanging the relative positions of wires to neutralize the effects of induction to or from other circuits or, to minimize interference pickup by the lead-in during reception. Tray Cable: A factory-assembled multiconductor or multipair control cable approved under the National Electrical Code for installation in trays. Triaxial: A three-conductor cable with one conductor in the center, a second circular conductor shield concentric with the first, and third circular conductor shield insulated from and concentric with the first and second, usually with insulation, and over a braid or impervious sheath overall. Triboelectric Noise: Noise generated in a shielded cable due to variations in capacitance between shielding and conductor as the cable is flexed. True Concentric: A cable in which each successive layer has a reversed direction of lay from the preceding layer. Triple Cable: A cable composed of three insulated single conductors and one bare conductor, all twisted together. It may or may not have a common covering of binding. Trunk Cable: See Feeder Cable. Tubing: A tube of extruded non-supported plastic material. Velocity of Propagation (VP): The speed of an electrical signal down a length of cable compared to speed in free space expressed as a percent. It is the reciprocal of the square root of the dielectric constant of the cable insulation. Volt: A unit of electromotive force. Voltage: The term most often used in place of electromotive force, potential difference or voltage drop to designate the electric pressure that exists between two points and is capable of producing a current when a closed circuit is connected between two points. Watt: A unit of electric power. Wave Form: A graphical representation of a varying quantity. Usually, time is represented on the horizontal axis, and the current or voltage value is represented on the vertical axis. Wave Length: The distance, measured in the direction of propagation, of a repetitive electrical pulse or waveform between two successive points that are characterized by the same phase of vibration. Wicking: The longitudinal flow of a liquid in a wire or cable due to capillary action. Wire: A conductor, either bare or insulated. Wire and Cable Marker: Device for identification marking of wire and cable. Wire and Cable Tying, Clamping, and Harnessing Devices: Tying tapes, lacing cords and flexible sleevings which are used for wire and cable bundling, harnessing and holding. Other devices include plastic ties or clamps, spiral-cut plastic tubing and plastic U-shaped trays or ducts. Wire and Lead Cutters: Tools for cutting that range from plier-type cutters to semiautomatic or fully automatic machines integrated with other wire processing operations such as stripping, forming and terminating. Technical Information Wire Gauge: A system of numerical designation of wire sizes. Wire Nut: A closed-end splice that is screwed on instead of crimped. Wire Wrapped Connection: A solderless connection made by wrapping bare wire around a square or rectangular terminal with a power or hand tool. Voltage Drop: The voltage developed across a component or conductor by the current in the resistance or impedance of the component or conductor. Wire Wrapping Tools: Portable electric tools and automatic stationary machines used to make solderless wrapped connections of wires to terminals. Wiring Closet: See Telecommunications Closet. Work Area (Work Station): A building space where the occupants interact with telecommunications terminal equipment. Wrapper: An insulating barrier applied as a sheet or tape wrapped around a coil periphery. Voltage Rating: The highest voltage that may be continuously applied to a wire in conformance with standards or specifications. Voltage Standing Wave Ratio (VSWR): The ratio of the maximum effective voltage to the minimum effective voltage measured along the length of a mis-matched radio frequency transmission line. Volume Resistivity (Specific Insulation Resistance): The electrical resistance between opposite faces of a 1 cm. cube of insulating material, commonly expressed in Ω/ centimeter. Wall Thickness: The thickness of the applied insulation or jacket. Water Absorption: A test to determine the water absorbed by a material after a given immersion period. Zytel®: DuPont’s trade name for nylon resins. Yield Strength: The minimum stress at which a material will start to physically deform without increase in load. Sections of this glossary are reprinted with permission from December, 1985 Issue of ELECTRONICS copyright 1985. Lake Publishing Corporation, 17730 W. Peterson Rd., Libertyville, IL 60048-0159 USA. Permission to reprint granted to the General Cable Corporation. No additional reproduction of this wire and cable glossary allowed without written permission. Vulcanization: A chemical reaction in which the physical properties of an elastomer are changed by reacting it with sulfur or other cross-linking agents. Waterblocked Cable: A cable constructed with no internal voids in order to allow no longitudinal water passage under a given pressure. 190