160 Technical Information Electronics Feedback: Energy that is extracted from a high- level point in a circuit and applied to a lower level. Positive feedback reduces the stability of a device and is used to increase the sensitivity or produce oscillation in a system. Negative feedback, also called inverse feedback, increases the stability of a system as the feedback improves stability and fidelity. Feeder Cable: In telecommunication or CATV systems, the transmission cable from the head end (signal pickup) to the trunk amplifier. Also called a trunk cable. Feedthrough: (1) A conductor that connects patterns on opposite sides of a PCB. Also called Interfacial connection. (2) A connector or terminal block, usually having double-ended terminals which permit simple distribution and bussing of electrical circuits. Ferrous: Composed of and/or containing iron. A ferrous metal exhibits magnetic characteristics. Ferrule: A short tube used to make solderless connections to shielded or coaxial cable. Fiber: A thread or threadlike structure. Also, a single discrete element used to transmit optical (light wave) information. Fiber Dispersion: (fiber optic) Pulse spreading in a fiber caused by differing transit times of various modes. Fiber Optics: A lightwave or optical communications system in which electrical information is converted to light energy, transmitted to another location through optical fibers, and is there converted back into electrical information. Fiber Tubing: A loose, crush-resistant cylinder applied over individual fibers to provide mechanical protection. Field: An area of influence around a magnet or electric charge. Field Coil: A suitable insulated winding to be mounted on a field pole to magnetize it. Figure 8 Cable: An aerial cable configuration in which the conductors and the steel strand which supports the cable are integrally jacketed. A cross-section of the finished cable approximates the figure “eight.” Filament: Fiber characterized by extreme length. Filled Cable: A telephone cable construction in which the cable core is filled with a material that will prevent moisture from entering or passing through the cable. Filler: (1) A material used in multiconductor cables to occupy large interstices formed by the assembled conductors. (2) An inert substance added to a compound to improve properties or decrease cost. Film: A thin plastic sheet. Fine Stranded Wire: Stranded wire with component strands of 36 AWG or smaller. Firestop: A material, device or assembly of parts installed in a cable system in a fire-rated wall or floor to prevent passage of flame, smoke or gasses through the rated barrier. Flame Resistance: The ability of a material not to propagate flame once the heat source is removed. Flammability: The measure of the material’s ability to support combustion. Flashover: A disruptive discharge around or over the surface of a solid or liquid insulator. Flat Braid: A woven braid of tinned copper strands rolled flat at time of manufacture to a specified width. Flat Cable: A cable with two smooth or corrugated but essentially flat surfaces. Flat Conductor: A wire having a rectangular cross-section as opposed to a round or square conductor. Flat Conductor Cable: A cable with a plurality of flat conductors. Flexfoil®: Proprietary aluminum laminated shielding tapes. Flex Life: The measurement of the ability of a conductor or cable to withstand repeated bending. Flexibility: The ease with which a cable may be bent. Flexible: That quality of a cable or cable component which allows for bending under the influence of outside force, as opposed to limpness which is bending due to the cable’s own weight. Floating: Referring to a circuit which has no connection to ground. Flux: (1) The lines of force which make up an electrostatic field. (2) The rate of flow of energy across or through a surface. (3) A substance used to promote or facilitate fusion. FNC: Federal Networking Council (formerly FRICC). Foamed Plastics: See Cellular Plastic. Foil: A thin, continuous sheet of metal. Free Connector: A connector for attachment to the free end of a wire or cable. Frequency: The number of times a periodic action occurs in a unit of time. The number of cycles that an electric current completes in one second. Frequency Response: The characteristic of a device denoting the range of frequencies over which it may be used effectively. Funnel Entry: Flared or widened entrance to a terminal or connector wire barrel. Fuse Wire: Wire made from an alloy that melts at a relatively low temperature. Fused Coating: A metallic coating which has been melted and solidified, forming a metallurgical bond to the base material. Fused Conductors: Individual strands of heavy tinned copper wire stranded together and then bonded together by induction heating. Fused Spiral Tape: A PTFE insulated hookup wire. The spiral wrapped conductor is passed through a sintering oven where overlaps are fused together. Gain: The increase of voltage, current or power over a standard or previous reading. Usually expressed in decibels. Galvanometer: An instrument for detecting or measuring small electrical current. Gas-Filled Cable: A self-contained pressure cable in which the pressure medium is an inert gas having access to the insulation. Gauge: A term used to denote the physical size of a wire. Giga: A numerical prefix denoting one billion (109). Gigahertz (GHz): A unit of frequency equal to one billion hertz. Gimmick: A short length of wire soldered onto a circuit component and used as a small adjustable capacitor. Graded-lndex: A type of optical fiber in which the refractive index of the core is in the form of a parabolic curve, decreasing toward the cladding. This type of fiber provides high bandwidth capabilities. Ground: A conducting connection, whether intentional or accidental, between an electrical circuit (e.g. telecommunications) or equipment and the earth, or to some conducting body that serves in place of the earth. Ground Conductor: A conductor in a transmission cable or line that is grounded. Ground Insulation: The insulation used between a winding and the magnetic core or other structural parts, usually at ground potential. Ground Loop: The generation of undesirable current flow within a ground conductor, owing to the circulation currents which originate from a second source of voltage. Ground Plane: Expanded copper mesh which is laminated into some flat cable constructions as a shield. Ground Potential: Zero potential with respect to the ground or earth. Hard Drawn Copper Wire: Copper wire that has not been annealed after drawing. Harness: An arrangement of wires and cables usually with many breakouts, which have been tied together or pulled into a rubber or plastic sheath, used to interconnect an electric circuit. Hash Mark Stripe: A non-continuous helical stripe applied to a conductor for identification. Heat Distortion: Distortion of flow of a material or configuration due to the application of heat. Heat Seal: Method of sealing a tape wrap jacket by means of thermal fusion. Heater Cord: Flexible stranded copper conductor, cotton wrapped, with rubber insulation and asbestos roving. Helical Stripe: A continuous, colored, spiral stripe applied to a conductor for circuit identification. Helix: Spiral winding. Henry: The unit of inductance. Hertz (Hz): A term replacing cycles-per-second as an indication of frequency. Heterogeneous Insulation: A cable insulating system composed of two or more layers of different insulating materials. High-Temperature Wire and Cable: Electrical wire and cables having thermal operating characteristics of 150°C and higher. High Voltage: Generally, a wire or cable with an operating voltage of over 600 volts. Holding Strength: Ability of a connector to remain assembled to a cable when under tension. Homogeneous Insulation: A complete cable insulation structure whose components cannot be identified as layers of different materials. Hook-up Wire: A wire used for low-current, low- voltage (under 1000 volts) applications within enclosed electronic equipment. Horizontal Cabling: The wiring/cabling between the telecommunications outlet/connector and the horizontal cross-connect. Horizontal Cross-Connect: A cross-connect of horizontal cabling to other cabling, e.g. horizontal, backbone or equipment. Hot Stamping: Method of alpha numerical coding. Identification markings are made by pressing heated type and marking foil into softened insulation surfaces. See Surface Printing. Hot Tin Dip: A process of passing bare wire through a bath of molten tin to provide a coating. Hybrid Cable: An assembly of two or more cables (of the same or different types or categories) covered by one overall sheath. Glossary
