A/D - Analog-to-digital.
Accessories - Mechanical devices, such as cable clamps, added to connector shells and other such hardware which is attachable to connectors to make up the total connector configuration.
Alloy - A mixture of two or more metals combined to achieve properties, such as a lower melting point or greater strength, that the individual metals do not possess.
Ambient - The atmospheric conditions surrounding a given item. Normally in terms of factors which influence or modify, such as temperature, humidity, etc.
Amplitude - The magnitude of variation in a changing quantity from its zero value. The word frequently requires modification–as with adjectives such as peak, maximum, rms, etc.–to designate the specific amplitude in question.
Analog - The representation of information by means of continuously variable signal.
Aramid Fibers - A class of heat-resistant and strong synthetic fibers. They are used in aerospace and military applications for ballistic rated body armor fabric and ballistic composites, in bicycle tires, and as an asbestos substitute. The name is derived from merging of “aromatic polyamide”. They are fibers in which the chain molecules are highly oriented along the fiber axis, so the strength of the chemical bond can be exploited.
Attenuation - The decrease of a signal with the distance in the direction of propagation. Attenuation may be expressed as the scalar ratio of the output power to the input power, or as the ratio of the output signal voltage to the input signal voltage.
AWG - American Wire Gauge. Standards for wire diameter.
Back Mounted (rear mounting) - When a connector is mounted from the inside of a panel or box with its mounting flange inside the equipment.
Backplane Panels - An interconnection panel into which PCB cards or other panels can be plugged. These panels come in a variety of designs ranging from a PC motherboard to individual connectors mounted in a metal frame. Panels lend themselves to automated wiring.
Bandwidth - The range of frequencies for which performance, with respect to certain characteristics, falls within specific limits.
Barrier Seal - A barrier seal is a seal preventing the passage of moisture or gases through the insulator and the gap between insulator and center conductor or outer conductor of a connector or adapter.
Base Material - Metal from which the connector, contact or other piece part accessory is made and on which one or more metals or coatings may be deposited.
Bayonet Coupling - A quick coupling device for plug and receptacle connectors, accomplished by rotation of a cam operating device designed to bring the connector halves together.
Bend Radius - Radius of curvature that a flat, round, fiber optic or metallic cable can bend without any adverse effects.
Bluetooth - A technology that enables data connections between electronic devices such as desktop computers, wireless phones, headphones, electronic organizers and printers in the 2.4 GHz range.
BNC (Bayonet Neill Concelman) - Coaxial connector with bayonet coupling mechanism. Available in 50 ohm and 75 ohm versions. Frequency range DC-4 GHz (50 ohm) and DC-1 GHz (75 ohm), respectively.
Body - Main, or largest, portion of a connector to which other portions are attached.
Bond Strength - Amount of adhesion between surfaces, e.g., in cemented ribbon cable.
Bonded Assembly - A connector assembly in which the components are bonded together using an electrically appropriate adhesive in a sandwich structure to provide sealing against moisture.
Bonding - The method used to produce good electrical contact between metallic parts of any device. Used extensively in automobiles and aircraft to prevent static buildup. Also refers to the connectors and straps used to bond equipment.
BPS (bits per second) - Often preceded by K (kilo/thousands) or M (mega/million).
Braid - A weave of metal or metal-clad fibers used as a shield covering for an insulated conductor or group of insulated conductors.
Braid Angle - The smaller of the two angles formed by the shielding strand and the axis of the cable being shielded.
Braid Carrier - A spool or bobbin on a braider which holds one group of strands or filaments consisting of a specific number of ends. The carrier revolves during braiding operations.
Braid Coverage - A calculated percentage which defines the completeness with which a braid or shield covers the surface of the underlying component.
Braid Ends - The number of strands used to make up one carrier. The strands are wound side by side on the carrier bobbin and lie parallel in the finished braid.
Breakdown Voltage - The voltage at which the insulation between two conductors is destroyed.
Breakout - The point at which a conductor or group of conductors is separated from a multi-conductor cable to complete circuits at various points along the main cable.
Broadband - A transmission facility that has a bandwidth (capacity) capable of carrying numerous voice, video and data channels simultaneously. Each channel operates on a different frequency. Cable TV is a broadband transmission.
Bulkhead - A term used to define a mounting style of connectors. Bulkhead connectors are designed to be inserted into a panel cutout from the rear (component side) or front side of the panel.
Bunch Strand - Conductors twisted together with the same lay and direction without regard to geometric pattern.
Bus-Bar Wire - Uninsulated tinned copper wire used as a common lead.
Butted Contact - When two conductors come together end-to-end, but do not overlap, with their axis in line.
Butyl Rubber - A synthetic rubber with good insulating properties.
C - Symbol designation for Capacitance (electrical), and Celsius (temperature).
Cable - An insulated conductor or multi-conductors twisted together.
Cable Assembly - A length of cable with connectors on one or both ends.
Cable Sheath - The protective covering applied to cables.
Cabling - The method by which a group of insulated conductors is mechanically assembled or twisted together.
CAD/CAM - Computer-aided design/Computer-aided manufacturing.
Capacitance (C) - That property of a system of conductors and dielectrics which permits the storage of electricity when potential difference exists between the conductors. Its value is expressed as a ratio of a quantity of electricity to a potential difference.
Capacitance Reactance - The opposition to alternating current due to the capacitance of a capacitor, cable or circuit. It is measured in ohms and is equal to 1/6.28fC where f is the frequency in Hz and C is the capacitance in farads.
Capacitor - Two conducting surfaces separated by a dielectric material. The capacitance is determined by the area of the surfaces, type of dielectric and spacing between the conducting surfaces.
Capillary Actions - The effect of surface tension that draws a liquid into a small opening.
Carrier Frequency - The electromagnetic wave frequency selected to transmit information. Optical carrier frequency is from the infrared, visible range or ultraviolet spectrum areas.
Cellular Polyethylene - Expanded or “foam” polyethylene, consisting of individual closed cells of inert gas suspended in a polyethylene medium, resulting in a desirable reduction of the dielectric constant.
Certificate of Compliance (C of C) - A certificate which is normally generated by a Quality Control Department, which shows that the product being shipped meets the customer’s specifications.
Certificate Test Report (CTR) - A report providing actual test data on cable. Tests are normally run by a Quality Control Department, which shows that the product being shipped conforms to test specifications.
Characteristic Impedance - Characteristic impedance of a uniform line is the ratio of an applied potential difference to the resultant current at the point where the potential difference is applied, when the line is of infinite length. Coaxial cable is such a uniform line.
Circular Mil - A term used to define cross-sectional areas using an arithmetic short-cut in which the area of a round wire is taken as “diameter in mils (0.001)” squared; hence, one circular mil is equal to pi/4 square mils.
Closed Entry Contact - A specially designed connector interface which controls the entry of the male pin from damaging the female contact.
Coaxial Cable - A cylindrical transmission line composed of a conductor centered inside a metallic tube or shield, separated by a dielectric material, and usually covered by an insulating jacket.
Cold Flow - Deformation of the insulation due to mechanical force of pressure (not due to heat softening).
Color Code - Method of identifying different conductors by means of colors, numbers, printing, etc.
Common Axis Cabling - In multiple cable constructions, a twisting of all conductors about a “common axis” with two conductor groups then selected as pairs. This practice yields smaller diameter constructions than does a separate axis construction, but tends to yield greater susceptance to EMI.
Composite Cable - A cable containing more than one gauge size or a variety of circuit types, e.g. pairs, triples, quads, coaxials, etc.
Concentric Stranding - A group of uninsulated wires twisted together and containing a center core with subsequent layers spirally wrapped around the core to form a single conductor.
Concentricity - In a wire or cable, the measurement of the location of the center of the conductor with respect to the geometric center of the surrounding insulation.
Conductance - The ability of a conductor to carry an electrical charge. The ratio of the current flow to the potential difference causing the flow. The reciprocal of resistance.
Conductivity - The ability of a material to allow electrons to flow, measured by the current per unit of voltage applied. It is the reciprocal of resistivity and is measured in Siemens (S) or Mhos.
Conductor - A wire or combination of wires not insulated from one another, suitable for carrying electric current.
Conduit - A tube or trough in which insulated wires and cables are passed.
Conformable Cable - See Semi-Flexible Cable.
Connector - A device used to physically and electrically join two or more conductors.
Connector Assembly - Includes housing and contact plus additional components such as hardware used to hold the assembly together and/or make the assembly a functional connector.
Connector Insertion Loss (Attenuation) - The loss of power in a mated pair of connectors.
Contact - The conducting part of an interconnect at the interface between the connector and the lead on the device being connected.
Contact Alignment - Defines the overall radial play which contacts shall have within the insert cavity so as to permit self-alignment of mated contacts. Sometimes referred to as amount of contact float.
Contact Cavity - A defined hole in the connector insert or housing into which the contact must fit.
Contact Durability - The number of insertion and withdrawal cycles that a connector must be capable of withstanding while remaining within the performance levels of the applicable specification.
Contact Engaging & Separating Force - Force needed to either engage or separate pins and socket contacts when they are in and out of connector inserts. Values are generally established for maximum and minimum forces. Performance acceptance levels vary by specification and/or customer requirements.
Contact Plating - Deposited metal applied to the basic contact metal to provide the required contact-resistance and/or wear-resistance.
Contact Pressure - Force which mating surfaces exert against one another.
Contact Resistance - Measurement of electrical resistance of mated contacts when assembled in a connector under typical service use. Electrical resistance is determined by measuring from the rear of the electrical area of one contact to the rear of the mating contact (excluding both crimps) while carrying a specified test current.
Contact Retention - Defines minimum axial load in either direction which a contact must withstand while remaining firmly fixed in its normal position within an insert.
Control Cable - A multi-conductor cable made for operation in control or signal circuits.
Convection - The transfer of heat from an object by movement of air surrounding the object.
Copolymer - A compound resulting from the polymerization of two different monomers.
Copper - A reddish metal that is an excellent conductor of electricity.
Copper-Clad - Steel with a coating of copper welded to it, as distinguished from copper-plated.
Corona - A localized discharge resulting from transient gaseous ionization in an insulating system when the voltage stress exceeds a critical value.
Corona Extinction Voltage (CEV) - The voltage below which previously initiated corona pulses cease.
Corrosion - The deterioration of a material by chemical reaction or galvanic action.
Coupling - The transfer of energy between two or more cables or components of a circuit.
Crazing - The minute cracks on the surface of plastic materials.
Creep - The dimensional change with time of a material under load.
Crimp - Act of compressing (deforming) a connector ferrule around a cable in order to make an electrical connection.
Crimping Dies - A term used to identify the shaping tools that, when moved toward each other, produce a certain desirable shape to the barrel of the terminal or contact that has been placed between them. Crimping dies are often referred to as die sets or as die inserts.
Crimping Termination - Connection in which a metal sleeve is secured to a conductor by mechanically crimping the sleeve with pliers, presses or crimp dies.
Crimping Tool - A term commonly used to identify a hand-held mechanical device or table press that is used to crimp a contact, terminal or splice.
Cross Talk - A magnetic or electrostatic coupling which causes the unwanted transfer of energy from one signal path (disturbing circuit) to another signal path (disturbed circuit).
Cross-Linked - A term denoting intermolecular bonds between long chain thermoplastic polymers, affected by chemical or irradiation techniques.
Cryogenic - Use of cables in very low temperature environments.
CSA - Canadian Standards Association.
CTIA - Cellular Telecommunications Industry Association.
Current, Alternating (AC) - An electric current that periodically reverses direction of electron flow. The rate at which a full cycle occurs in a given unit of time (generally a second) is called the frequency of the current.
Current, Direct (DC) - Electric current whose electrons flow in one direction only. It may be constant or pulsating as long as its movement is in the same direction.
Cut-off - The frequency above which a coaxial device will support electrical modes other than the principal TEM (transverse electromagnetic) mode. This sets an upper limit to the coaxial line’s normal useful frequency range, distorting pulses and modulation envelopes.
Cut-through Resistance - The ability of a material to withstand mechanical pressure without damage.
CXC - Coaxial Cable, CSA (Canadian Standards Association) Cable Designation.
Cycle - One complete sequence of values of an alternating quantity, including a rise to maximum in one direction and of return to zero. The number of cycles occurring in one second is called the frequency.
Cycle Life - The number of repetitive flex motions that a wire or cable can withstand prior to breakdown.
D/A - Digital-to-analog
DAR (Designated Airworthiness Representative) - Delegate of the FAA with the ability to conform production articles as adhering to the approved design engineering documentation.
DER (Designated Engineering Representative) - Delegate of the FAA with the ability to issue a statement of compliance for engineering data to the FAA airworthiness regulations.
DMIR (Designated Manufacturing Inspection Representative) - Delegate of the FAA with the ability to inspect production articles at a specific approved FAA PMA facility and issue form 8130-3 for the product.
dBm - Relative measure of signal power where the reference (0 dBm) is equal to one milliwatt. See also decibel.
DC Resistance - See Resistance.
Decibel (dB) - A relative unit without dimensions calculated as ten times the logarithm to the base 10 of a power ratio or as twenty times the logarithm to the base 10 of a voltage ratio. Note: What is commonly measured as VSWR in the RF world is referred to as return loss and measured in dB in the CATV industry.
Delay Line - A cable that delays electrical signals by a specified amount of time.
Denier - Unit of measure for the linear mass density of fibers. It is defined as the mass in grams per 9000 meters.
Derating Factor - A factor used to reduce the current-carrying capacity of a wire when used in environments other than that for which the value was established.
Dewetting - A situation where a lead was at one point in the soldering process wetted by the solder, but due to extended time or temperature, the presence of intermetallics, volatiles or other causes, has become withdrawn from the wetted surface.
Dielectric - In a coaxial cable, the insulation between inner and outer conductor. It significantly influences electrical characteristics such as impedance, capacitance and velocity of propagation.
Dielectric Breakdown - Any change in the properties of a dielectric that causes it to become conductive. Normally a catastrophic failure of an insulation because of excessive voltage.
Dielectric Constant - Also called permittivity. That property of a dielectric which determines the amount of electrostatic energy that can be stored by the material when a given voltage is applied to it. Actually, the ratio of the capacitance of a capacitor using the dielectric to the capacitance of an identical capacitor using a vacuum as a dielectric.
Dielectric Heating - The heating of an insulating material when placed in a radio-frequency field, caused by internal losses during the rapid polarization reversal of molecules in the material.
Dielectric Loss - In a coaxial cable, the losses caused by transformation of electromagnetic energy into heat within the dielectric material.
Dielectric Strength - The voltage which an insulating material can withstand before breakdown occurs.
Dielectric Withstanding Voltage - The maximum potential gradient that a dielectric material can withstand without failure.
Digital - (1) Pertaining to the utilization of discreet integral numbers in a given base to represent all the quantities that occur in a problem or a calculation. It is possible to express in digital form all information stores, transferred or processed by a dual-state condition; e.g., on-off, open-closed and true-false. (2) Compare with analog.
Digital Signal - An electrical signal which possesses two distinct states (on/off, positive/negative).
Digital Signal Processor (DSP) - A microprocessor that digitizes analog signals.
DIN 7/16 - 50-ohm coaxial connector with screw-type coupling mechanism providing excellent intermodulation characteristics. Suitable for medium to high power applications. Frequency range DC - 7.5 GHz.
Dip Solder Terminal - The terminals on a connector which are inserted into holes in the PC board and then soldered in place.
Direct Current (DC) - An electric current which flows in only one direction.
Dissipation - Unusable or lost energy, such as the production of unused heat in a circuit.
Distortion - An unwanted change or addition to a signal or waveform when it is amplified. This definition excludes noise, which is an extraneous signal superimposed on the desired signal.
Drain Wire - An uninsulated wire in contact with a shield throughout its length. Used for terminating the shield.
Drawing - The process of pulling metal through a die or a series of dies to achieve a desired diameter.
Duct - An underground or overhead tube for carrying electrical cables.
Dummy Load - A dissipative device used at the end of a transmission line or waveguide to convert transmitted energy into heat, so essentially no energy is radiated outward or reflected back to its source.
Dust Cap - A device attached to a connector to provide protection against dust and foreign debris.
E - Symbol for voltage (electromotive force).
Earth - British terminology for zero-reference ground.
Eccentricity - A measure of a conductor's location with respect to the circular cross-section of the insulation. Expressed as a percentage of center displacement of one circle within the other.
ECIA - Electronic Components Industry Association
ECTFE - Ethylene chloro-trifluoroethylene (Halar®).
EIA - Electronic Industries Alliance. The EIA ceased operations in February 2011 and transferred custody of EIA Standards to the Electronic Components Industry Association (ECIA)
Elastomer - A rubber-like synthetic polymer, such as silicon rubber.
Electromagnetic - Referring to the combined electric and magnetic fields caused by electron motion through conductors.
Electromagnetic Compatibility (EMC) - Requires that electronic systems be able to tolerate a specified degree of interference (EMI/EMP/Indirect Lightning Effects) and not generate more than a specified amount of interference.
Electromagnetic Coupling - The transfer of energy by means of a varying magnetic field. Inductive coupling.
Electromagnetic Interference (EMI) - Any electromagnetic emission from a device or system that interferes with the normal operation of another device or system. A burst of electromagnetic radiation that results from an explosion (usually from the detonation of a nuclear weapon) and/or a suddenly fluctuating magnetic field.
Electron Volt (eV) - A measure of the energy gained by an electron falling through an electric field produced by one volt.
Electroplating - A method of electrically depositing metals of very precise compositions and thickness onto a base metal.
Electrostatic - Pertaining to static electricity or electricity at rest. Example: an electric charge.
Electrostatic Coupling - The transfer of energy by means of a varying electrostatic field. Capacitive coupling.
EMC - Electromagnetic compatibility.
EMF - Electromotive force (voltage).
EMI - Energy generated by outside sources, such as lighting systems and electric motors, which is received by copper data/voice cable and interferes with transmission.
EMP - Electromagnetic pulse.
Energy Dissipation - Loss of energy from a system due to the conversion of work energy into an undesirable form, usually heat. Dissipation of electrical energy occurs when current flows through a resistance.
EPDM - Ethylene propylene diene monomer rubber. A material with good electrical insulating properties.
Epoxy - An adhesive used in the connector termination process.
EPR - Ethylene-propylene rubber. A material with good electrical insulating properties.
Equilay - More than one layer of helically laid wires with the length of the lay the same for each layer.
ETFE - Ethylene tetrafluoroethylene (Teflon®).
Eutectic Solder - The most common solder alloy because of its low melting point (183°C/361°F). Can be any alloy that changes from a liquid to a solid state at a defined temperature.
Eutectic System - A eutectic system is a mixture of chemical compounds or elements that has a single chemical composition that solidifies at a lower temperature than any other composition made up of the same ingredients. This composition is known as the eutectic composition and the temperature at which it solidifies is known as the eutectic temperature. On a phase diagram the intersection of the eutectic temperature and the eutectic composition gives the eutectic point. Non-eutectic mixtures will display solidification of one component of the mixture before the other. Not all binary alloys have a eutectic point; for example, in the silver-gold system the melt temperature and freeze temperature both increase monotonically as the mix changes from pure silver to pure gold.
Expanded Diameter - Diameter of shrink tubing as supplied. When heated, the tubing will shrink to its extruded diameter.
Expanded Polyethylene - See Cellular Polyethylene
External Interference - The effects of electrical waves or fields which cause spurious signals other than the desired intelligence, e.g. noise.
Extrusion - A process of continuously applying an insulation over a conductor or jacket (rubber or plastic compounds).
F - Symbol for frequency or farad.
FAA - Federal Aviation Administration.
FAA Form 8110-3 - A document issued in support of an FAA STC by a DER to show that a specific set of technical data has complied with the FAA regulations.
Farad (F) - The capacitance of a capacitor in which a charge of 1 coulomb produces a 1-volt potential difference between its terminals.
Fatigue Resistance - Resistance of metal crystallization which leads to conductors breaking from flexing.
FCC - Federal Communications Commission.
Feed-through - A connector or terminal block, usually having double-ended terminals which permits simple distribution and bussing of electrical circuits. Also used to describe a bushing in a wall or bulkhead separating compartments at different pressure levels, with terminations on both sides.
FEP (Fluorinated Ethylene-Propylene) - Copolymer of PTFE and hexafluoropropylene. Electrical properties similar to PTFE, but temperature limited to 400°F (204°C).
Ferrous - Composed of and/or containing iron. A ferrous metal exhibits magnetic characteristics.
Ferrule - A short tube to make solderless connections to shielded or coaxial cable (e.g. as in crimping).
FHPE - Foamed high-density polyethylene.
Field - An area through which electric and/or magnetic lines of force pass.
Fillers - Non-conducting components cabled with the uninsulated conductors or optical fibers to impart roundness, flexibility, tensile strength, or a combination of all three, to the cable.
Flame Resistance - The ability of material not to propagate flame once the flame source is removed.
Flammability - The measure of a material’s ability to support combustion.
Flange - A projection extending from, or around the periphery of, a connector and provided with holes to permit mounting the connector to a panel, or to another mating connector half.
Flex Life - The ability of a cable to bend many times before breaking.
Flexibility - The ability of a cable to bend in a short radius (also see Limpness).
Fluorocopolymer - Generic term for PVDF. See also Kynar®.
Foam Polyethylene - See Cellular Polyethylene.
Foamed Plastics - Insulations having a cellular structure.
Form 1 - A document issued in support of an EASA STC to show conformance of production articles to the design engineering drawings. This is in addition to a standard C of C.
FRD (Fire Retardant) - A rating used for cable with Teflon or equivalent jacket and insulation. Use this cable when local fire codes call for low flame and low smoke, or when cable is run through a forced-air plenum.
Frequency (f) - The number of times an alternating current repeats its cycle in one second.
Frequency Modulation (FM) - A scheme for modulating a carrier frequency in which the amplitude remains constant but the carrier frequency is displaced in frequency proportionally to the amplitude of the modulating signal. An FM broadcast is practically immune to atmospheric and man-made interference.
Frequency Response - The characteristic of a device denoting the range of frequencies over which it may be used effectively.
Fretting Corrosion - A form of accelerated oxidation that appears at the interface of contacting materials undergoing slight cyclic relative motion. All non-noble metals (tin) are susceptible to some degree of fretting corrosion and will suffer contact resistance increases.
Front Mounted (front mounting) - A connector is front mounted when it is attached to the outside or mating side of a panel. A front mounted connector can only be installed or removed from the outside of the equipment.
Gauge - Term to denote size of wire, as in American Wire Gauge (AWG). Can also be used in reference to determining connector interface critical dimensions.
Gain - The increase of voltage, current or power over a standard or previous reading. Usually expressed in decibels.
Geophysical Cable - Cable used in exploring for underground oil deposits.
GHz - See Gigahertz.
Gigahertz (GHz) - One billion cycles per second (109 cps).
GND - Ground.
GPIB - General purpose interface bus. Also known as the IEEE-488 bus. One method of providing communication between various test equipment and controllers.
GPS - Global Positioning System.
Ground (GND) - An electrical term meaning to connect to the earth or other large conducting body to serve as an earth, thus making a complete electrical circuit.
Ground Fault - A failure of transmission involving insulation-to-shield or insulation-to-ground wire.
Ground Loop - A completed circuit between shielded pairs of a multiple pair created by random contact between shields. An undesirable circuit condition in which interference is created by ground currents when grounds are connected at more than one point.
Ground Potential - The potential of the earth. A circuit, terminal or chassis is said to be at ground potential when it is used as a reference point for other potentials in the system.
H - Symbol designation for magnetic intensity and henry (a unit of inductance).
Hard Drawn - Refers to metal that has not been annealed.
Harness - Group of conductors, and cables for special hook-ups.
Hash Mark Stripe - A non-continuous helical stripe applied to a conductor for identification.
Heat Distortion - Distortion of a material due to the effects of heat.
Heat Shock - Test to determine the stability of a material when exposed to a sudden high-temperature change for a short period of time.
Heat Treating - A process that uses precise heating and cooling of metals in order to optimize internal stresses and spring properties.
Helical Stripe - A continuous, colored, spiral stripe applied to a conductor for circuit identification.
Henry (H) - A practical unit of inductance that will produce an electromotive force of one volt when the current changes at the rate of one ampere per second.
Hermaphroditic Connector - A connector where both mating members are exactly alike at their mating face. There are no male or female members, but provisions have been made to maintain correct polarity, hot lead protection, sealing and coupling. Most commonly used in the industry are 7-mm or APC-7 connectors.
Hermaphroditic Contacts - Contacts in which both mating elements are precisely alike at their mating face.
Hermetic Seal - Hermetically sealed connectors provide contacts bonded to the connector by glass. They permit maximum leakage rate of gas through the connector of 1.0 micron ft/hr at one atmosphere pressure for special applications.
Hertz (Hz) - International standard term for cycles per second (e.g. 60 cycles per second is equal to 60 hertz or 60 Hz). Named after the German physicist Heinrich R. Hertz.
High Frequency (HF) - The band from 3 MHz to 30 MHz in the radio spectrum, as designated by the Federal Communications Commission.
Hipot - Term used for high-voltage dielectric test and/or equipment.The acronym stands for High Potential.
Hook-up Wire - Small, single conductor wire used to hook up electrical parts of instruments for low current and voltage.
Hygroscopic - Readily absorbing and retaining moisture.
Hysteresis - The lag between a cause and effect; temperature change and resultant electrical phase changes in cable when the temperature returns to the initial point of measurement.
I - Symbol used to designate current.
I2R - Formula for power in watts, where I = current in amperes, R = resistance in ohms. Also see Watt.
IEC - International Electrotechnical Commission.
IEEE (Institute of Electrical and Electronic Engineers) - An international professional society that issues its own standards and is a member of ANSI and ISO.
IF - Intermediate frequency.
IM/PIM (Passive Intermodulation) - The generation of new (and in the case of cable assemblies undesirable) signals (intermodulation products) due to the non-linear characteristics of transmission elements.
Impact Strength - A test for determining the mechanical punishment a cable can withstand without physical or electrical breakdown by impacting with a given weight, dropped a given distance, in a controlled environment.
Impedance - The total opposition that a circuit offers to the flow of alternating current or any other varying current at a particular frequency.
Impedance Match - A condition whereby the impedance of a particular circuit cable or component is the same as the impedance of the circuit, cable or device to which it is connected.
Impedance Matching Stub - A section of transmission line or pair of conductors cut to match the impedance of a load. Also called matching stub.
Impedance Matching Transformer - A transformer designed to match the impedance of one circuit to that of another.
Impedance, Characteristic - In a transmission cable of infinite length, the ratio of the applied voltage to the resultant current at the point the voltage is applied. Or the impedance which makes a transmission cable seem infinitely long, when connected across the cable’s output terminals.
Indirect Lightning Effects - Refers to the damage to or malfunction of electronic systems that results from a nearby lightning discharge.
Inductance - The property of a circuit or circuit element that opposes a change in current flow, thus causing current changes to lag behind voltage changes. It is measured in Henrys.
Induction - The phenomenon of a voltage, magnetic field or electrostatic charge being produced in an object by lines of force from the source of such fields.
Induction Heating - Heating a conducting material by placing it in a rapidly changing magnetic field. The changing field induces electric currents in the material and I2R losses account for the resultant heat.
Input - A signal (or power) which is applied to a piece of electric apparatus or the terminals on the apparatus to which a signal or power is applied.
Insert - The part which holds the connector contacts in their proper arrangement and electrically insulates them from each other and from the shell.
Insertion Loss - The loss in load power due to the insertion of a component, connector or device at some point in a RF transmission system. Generally expressed in decibels as the ratio of the power received at the load before insertion of the apparatus, to the power received at the load after insertion.
Insulation - A material having high resistance to the flow of electric current. Often called a dielectric in microwave cable.
Insulation Resistance - The electrical resistance of the insulating material (determined under specified conditions) between any pair of contacts, conductors or grounding device in various combinations.
Insulation Stress - The molecule separation pressure caused by a potential difference across an insulator. The practical stress on insulation is expressed in volts per mil.
Interconnecting Cable - The wiring between modules, between units, or the larger portions of a system.
Interconnection - Mechanically joining assemblies together to complete electrical circuits.
Interface - The two surfaces on the contact side of both halves of a multiple-contact connector which face each other when the connector is assembled.The region where two systems, or a major and a minor system, meet and interact with each other.
Interference - Disturbances of an electrical or electromagnetic nature that introduce undesirable responses into other electronic equipment.
Intermediate Frequency - A frequency to which a signal is converted for ease of handling. Receives its name from the fact that it is an intermediate step between the initial and final conversion or detection stages.
Intermetallic - Chemical compounds formed between the metals present in the solder, base metal and protective plating. Intermetallic formation is necessary for good solder joints, but excessive intermetallics can cause brittleness.
Intermodulation Distortion (IMD) - A phenomenon that occurs when two or more fundamental frequencies are present in an electronic circuit and produce spurious signals that are sum and differences of the fundamental frequencies.
Interstices - Space between adjacent structures.
Ionization - The formation of ions. Ions are produced when polar compounds are dissolved in a solvent and when a liquid, gas or solid is caused to lose or gain electrons due to the passage of an electric current.
Ionization Voltage - The potential at which a material ionizes. The potential at which an atom gives up an electron.
IR Drop - The designation of a voltage drop in terms of current and resistance.
Irradiated - Exposure to high-energy radiation resulting in cross-linking of molecules.
ISO - International Standards Organization.
Isolation - The ability of a circuit or component to reject interference, usually expressed in dB.
Ionization - The formation of ions. Ions are produced when polar compounds are dissolved in a solvent and when a liquid, gas or solid is caused to lose or gain electrons due to the passage of an electric current.
Ionization Voltage - The potential at which a material ionizes. The potential at which an atom gives up an electron.
IR Drop - The designation of a voltage drop in terms of current and resistance.
Irradiated - Exposure to high-energy radiation resulting in cross-linking of molecules.
ISO - International Standards Organization.
Isolation - The ability of a circuit or component to reject interference, usually expressed in dB.
Jack - A connecting device into which a plug can be inserted to make circuit connections. The jack may also have contacts which open or close to perform switching functions when the plug is inserted or removed. See also receptacle.
Jacket - An outer non-metallic protective cover applied over an insulated wire or cable.
K-Band - Radio spectrum in the 18GHz to 27GHz range used by satellite communications systems.
Ka-Band - Radio spectrum in the 27GHz to 40GHz range used by satellite communications systems.
KeV - 1000 electron volts.
KEVLAR® - An aramid fiber used to provide crush resistance and pulling strength in a fiber cable. KEVLAR® is a registered trademark of E.I. du Pont de Nemours and Company.
Kilo - Prefix meaning thousand.
Kilometer (km) - 1000 meters or 3,281 feet (0.621 miles); the standard measurement for fiber optics.
KPSI - Tensile strength in thousands of pounds per square inch.
Ku-Band - Radio spectrum in the 12 GHz to 18 GHz range used by satellite communication systems.
kV - Kilovolt (1000 volts). Also see volt and voltage.
kVA - Kilovolt Ampere. A designation of power in terms of voltage and current.
KW - Kilowatt. A unit of electrical power.
Kynar® - A DuPont trademark for a fluorocarbon insulation rated -65°C to 135°C.
L - Symbol for inductance.
Lay - Pertaining to wire and cable, the axial distance required for one cabled conductor or conductor strand to complete one revolution about the axis around which it is cabled.
Lay Direction - The direction of the progressing spiral twist in a cable while looking along the axis of the cable away from the observer. The lay direction can be either “left” or “right”.
Lead-in - The cable that provides the path for RF energy between the antenna and the receiver or transmitter.
Leakage - The undesirable passage of current over the surface of or through an insulator.
Level - A measure of the difference between a quantity or value and an established reference.
Life Cycle - A test to determine the length of time before failure in a controlled, usually accelerated, environment.
Light Emitting Diode (LED Source) - A semiconductor device that emits incoherent light formed by the P-N junction. Light intensity is roughly proportional to electrical current flow.
Limpness - The ability of a cable to lay flat or conform to a surface as with microphone cables (also see Flexibility).
Line Drop - A voltage loss occurring between any two points in a power or transmission line. Such loss, or drop, is due to the resistance, reactance or leakage of the line.
Line Impedance - Impedance as measured across the terminals of a transmission line; frequently the characteristic impedance of the line.
Line Level - Refers to the output voltage level of a piece of electronic equipment. Usually expressed in decibels (e.g., O dBv).
Line Voltage - The value of the potential existing on a supply or power line.
Load - A device that consumes power from a source and uses that power to perform a function.
Long-Wire Antenna - Any conductor length in excess of one-half of a wavelength. In a residential television installation, a horizontal run or unshielded lead-in will act as a long-wire antenna and introduce additional signal on top of the regular antenna signal causing ghosts, echoes and pixelation.
Longitudinal Shield - A tape shield, flat or corrugated, applied parallel to the axis of the core being shielded.
Longitudinal Shrinkage - A term generally applied to shrink products denoting the discrete axial length lost through heating in order to obtain the recovered diameter.
Loop Resistance - The total resistance of two conductors measured round trip from one end.
Loss - The portion of energy applied to a system that is dissipated and performs no useful work.
Lossy - Having poor efficiency.
Low Frequency (LF) - A band of frequencies extending from 30 kHz to 300 kHz in the radio spectrum, designated by the Federal Communications Commission.
Low Loss - A cable that has relatively small power loss over long lengths.
Low Loss Dielectric - An insulating material that has a relatively low dielectric loss, such as formed polyethylene or microporous Teflon.
Low Noise Cable - Cable specially constructed to avoid spurious electrical disturbances caused by mechanical movements.
mA - Milliampere (one-thousandth of an ampere). A measurement of electrical current.
Magnetic Field - The region within which a body or current experiences magnetic forces.
Magnetic Flux - The rate of flow of magnetic energy across or through a surface (real or imaginary).
Magnetic Noise - Caused by a change in current level, e.g., AC powerline (creates magnetic field around that cable), this magnetic field causes the magnetic noise.
Mastic - Meltable coating used on the inside of some shrink products which, when heated, flows to encapsulate the interstitial air voids.
Mating Face Seal - A mating face seal is a seal preventing the passage of moisture or gases into or out of the connecting interface of two connectors in mated condition.
MCX (Micro coaxial) - Micro coaxial connector with snap-on coupling mechanism. Available in 50 ohm and 75 ohm versions. Frequency range DC-6 GHz.
Mega - Prefix meaning million.(106)
Megahertz (MHz) - Unit of frequency equal to one million hertz (106 cycles per second).
Meter (m) - One meter equals 3.281 feet.
MHO - The unit of conductance equal to the reciprocal of the unit of resistance (ohm). The Siemen (S) is replacing the mho as the standard unit of conductance.
MHV (Miniature High Voltage) - Coaxial connector with bayonet coupling mechanism. Working voltage 2.2 kV DC.
Micro - Prefix meaning one-millionth.(10-6)
Microfarad (MF) - One-millionth of a farad (uf, ufd, mf and mfd are common abbreviations).
Micromicrofarad - One millionth of a microfarad (uuf, uufd, mmfd are common abbreviations). Also a picofarad (pf or pfd).
Micron (um) - Millionth of a meter = 10-6 meter.
Microphonics - Noise caused by mechanical excitation of a system component. In a single-conductor microphone cable, for example, microphonics can be caused by the shield rubbing against the dielectric as the cable is flexed.
Microstrip - A type of transmission line configuration which consists of a conductor over a parallel ground plane, and separately by a dielectric.
Microwave - That portion of the electromagnetic spectrum lying between the far infrared and the Very High Frequency (VHF) conventional radio frequency range. The microwave frequency range extends from 300 MHz to 300 GHz. Microwaves are usually used in point-to-point communications because they are easily concentrated into a beam.
MIL - Military (e.g. as in Military Standards).
MIL-DTL-17 - DSCC specification for Radio Frequency cables, flexible and semi-rigid.
Milli - Prefix meaning one-thousandth.
Millimeter (mm) - One millimeter equals 0.03937 inches.
Mismatch (Connector Impedance or Line Impedance) - The condition in which the impedance of a source does not match or equal the impedance of the connected load. This reduces power transfer by causing reflection.
MMCX - Miniature micro-connector with snap-on coupling mechanism. Available in 50 ohm and 75 ohm versions. Frequency range DC-6 GHz.
Mode - A single electromagnetic wave traveling in a cable.
Modulation - Altering the characteristics of a carrier wave to convey information. Modulation techniques include amplitude, frequency, phase, plus many other forms of on-off digital coding.
Modulus of Elasticity - The ratio of stress to strain in an elastic material.
Moisture Absorption - The amount of moisture, in percentage, that a material will absorb under specified conditions.
Moisture Resistance - The ability of a material to resist absorbing moisture from the air or when immersed in water.
Mono Filament - A single-strand filament as opposed to a braided or twisted filament.
Monomer - The basic chemical unit used in building a polymer.
Multi-conductor - A combination of 2 or more conductors cabled together under a common jacket.
mV (Millivolt) - One thousandth of a volt.
mW (Milliwatt) - One thousandth of a watt.
Mylar® - DuPont trademark for polyethylene terephtalate (polyester) film.
N (Neill) - Coaxial connector with screw-type coupling mechanism. Available in 50 ohm and 75 ohm version. Frequency range DC-18 GHz (50 ohm) and DC-1 GHz (75 ohm), respectively.
Nanometer (nm) - A unit of measure equal to 10-9 (one billionth) meter. Used to measure the wavelength of light.
Nanosecond (ns) - One billionth of a second (10-9 seconds).
NBR - Butadiene-acrylonitrile copolymer rubber, a material with good oil and chemical resistance.
NEC - National Electrical Code.
NEMA - National Electrical Manufacturers Association.
Neoprene - A synthetic rubber with good resistance to oil, chemical and flame. Also called polychloroprene.
Noise - Random electrical signals, generated by circuit components or by natural disturbances.
Nomex® - A DuPont trademark for temperature-resistant, flame-retardant nylon.
Nylon - An abrasion-resistant thermoplastic with good chemical resistance.
OEM - Original Equipment Manufacturer.
OFHC - Abbreviation for oxygen-free, high-conductivity copper. It has no residual deoxidant, 99.95% minimum copper content and an average annealed conductivity of 101%.
Ohm - The unit of measurement for electrical resistance. A circuit is said to have a resistance of one ohm when an applied emf of one volt causes a current of one ampere to flow.
Ohm’s Law - Stated E = IR, I = E/R, or R = E/I, the current I in a circuit is directly proportional to the voltage E, and inversely proportional to the resistance R.
OSHA - Occupational Safety and Health Act relating to safety in places of employment.
Outgassing - Percentage of a gas released during exposure of insulation or jacketing material to a low-pressure atmosphere or vacuum.
Output - The useful power or signal delivered by a circuit or device, or the terminals on the device from which the signal is extracted.
Overlap - The amount of trailing edge laps over the leading edge of a tape wrap.
Ozone - Extremely reactive form of oxygen, normally occurring around electrical discharges and present in the atmosphere in small but active quantities. In sufficient concentrations, it can break down certain rubber insulations under tension (such as a bent cable).
Pairing - The union of two insulated single conductors through twisting.
Panel Seal - A panel seal is a seal preventing the passage of moisture or gases through the gap between the mounting hole of the panel and the connector body of the fixed connector.
PE - Abbreviation for polyethylene. A thermoplastic insulation having excellent electrical properties.
Peak - The maximum instantaneous value of a varying current or voltage.
Periodicity - Uniformly spaced variations in the insulation diameter of a transmission cable that result in reflections of a signal.
Permeability (magnetic) - The measure of how much better a material is than air as a path for magnetic lines of force. Air is assumed to have a permeability of 1.
Permittivity - The ratio of the capacitance of a capacitor using the dielectric to the capacitance of an identical capacitor using a vacuum as a dielectric. Also see Dielectric Constant.
Permittivity, Relative - Synonymous term for relative dielectric constant Er.
Phase - An angular relationship between waves.
Phase Shift - Change in phase of a voltage or current after passing through a circuit or cable.
Phase Stability - Variation of the electrical length of a cable that can result from temperature or mechanical stress due to bending or torsion.
Pick - Distance between two adjacent crossover points of braid filaments. The measurement in picks per inch indicates the degree of coverage.
Pico - Prefix meaning one-millionth of one-millionth (10-12).
Picofarad (pF) - One-millionth of one-millionth of a farad. A micromicrofarad or picofarad (abbreviation pf).
Pin Contact - A male-type contact, usually designed to mate with a socket or female contact. It is normally connected to the "dead" side of a circuit.
Plastic - High polymeric substances, including both natural and synthetic products, but excluding the rubbers that are capable of flowing under heat and pressure.
Plastic Deformation - Change in dimensions under load that is not recovered when the load is removed.
Plasticizer - A chemical added to plastics to make them softer and more flexible.
Plated Through-Hole - A hole through a printed circuit board that has been electroplated and into which a lead is placed and soldered for electrical and mechanical connection.
Plenum - A compartment or chamber to which one or more air ducts are connected and that forms part of the air distribution system.
Plenum Cable - Cable made of fire-retardant material that meets electrical code requirements (UL 910) for low smoke generation and installation in air spaces.
Plug - In coaxial RF connectors the plug is usually the movable portion, and is usually attached to a cable or removable assembly. Plugs mate with receptacles, jacks, outlets, etc.
Polybutadiene - A type of synthetic rubber often blended with other synthetic rubbers to improve their properties.
Polychloroprene - Chemical name of neoprene.
Polyester - Polyethylene terephthalate, which is used extensively in the production of a high-strength moisture-resistant film used as a cable core wrap.
Polyethylene (PE) - A thermoplastic material having excellent electrical properties.
Polymer - A substance made of many repeating chemical units or molecules. The term polymer is often used in place of plastic, rubber or elastomer.
Polyolefin - A family of thermoplastics based upon the unsaturated hydrocarbons known as olefins. When combined with butylene or styrene polymers, they form compounds such as polyethylene and polypropylene.
Polypropylene - A thermoplastic similar to polyethylene but stiffer and having a higher softening point (temperature).
Polyurethane - Broad class of polymers noted for good abrasion and solvent resistance. Can be solid or cellular form.
Polyvinyl Chloride (PVC) - A general purpose thermoplastic used for wire and cable insulation and jackets.
Porosity - Multiple voids in an insulation or jacket wall.
Potting - Sealing by filling with a substance to exclude moisture.
Power - The amount of work per unit of time. Usually expressed in watts and equal to I2R.
Power Factor (Fp) - The ratio of resistance to impedance. The ratio of an actual power of an alternating current to apparent power. Mathematically the cosine of the angle between the voltage applied and the current resulting.
Power Loss - The difference between the total power delivered to a circuit, cable or device and the power delivered by that device to a load.
Power Ratio - The ratio of power appearing at the load to the input power. Expressed in dB, it is equal to 10 log10 (P2/P1) where P1 is input power and P2 is the power at that load.
Primary Insulation - The first layer of non-conductive material applied over a conductor, whose prime function is to act as electrical barrier (see insulation).
Propagation Delay - Time required for an electronic digital device, or transmission network to transfer information from its input to its output.
Prototype - A model suitable for use in the complete evaluation of form, design and performance.
PSI - Pounds per square inch.
PTFE (polytetrafluoroethylene) - The thermally most stable and chemically most resistant carbonaceous compound. It is unaffected by sunlight, moisture, and virtually all chemicals. Temperature range is -200°C to +260°C / -392°F to +500°F. Electrical properties are very constant over temperature and wide range of frequencies.
Pulling Eye - A device fastened to a cable to which a hook may be attached in order to pull the cable into or from a duct.
Pulse - A current or voltage which changes abruptly from one value to another and back to the original value in a finite length of time. Used to describe one particular variation in a series of wave motions.
Pulse Width - The length of time that the pulse voltage is at the transient level. Electronic pulse widths are usually in the millisecond (10-3), microsecond (10-6) or nanosecond (10-9) range.
PVC (Polyvinyl Chloride) - The material most commonly used for the insulation and jacketing of cable.
PVD - Polyvinylidene Fluoride (see also Kynar®).
PVDF - Polyvinylidene Fluoride (see also Kynar®)
QPL - Qualified Parts List.
Radio Frequency - The frequencies in the electromagnetic spectrum that are used for radio communications.
Range - Number of sizes of connectors or cables of a particular type.
Reactance - A measure of the combined effects of capacitance and inductance on an alternating current. The amount of such opposition varies with the frequency of the current. The reactance of a capacitor decreases with an increase in frequency; the opposite occurs with an inductance.
Receptacle - Usually the fixed or stationary half of a two-piece multiple contact connector. Also the connector half usually mounted on a panel and containing socket (female) contacts.
Recovered Diameter - Diameter of shrinkable products after heating has caused it to return to its extruded diameter.
Reflection - The change in direction (or return) of waves striking a surface. For example, electromagnetic energy reflections can occur at an impedance mismatch in a transmission line, causing standing waves. See VSWR.
Reflection Coefficient - The ratio of the amplitude of the reflected wave to the amplitude of the incident wave in a transmission line.
Reflection Loss - The part of a signal which is lost due to reflection of power at a line discontinuity.
Repeatability - The amount of power lost due to the number of matings (de-matings) a connector experiences.
Repeater - Devices that receive a radio signal, amplify it and retransmit it in a new direction. Used in wireless networks to extend the range of base station signals, thereby expanding coverage within limits more economically than by building additional base stations. Repeaters typically are used for buildings, tunnels or difficult terrain.
Resin - A synthetic organic material formed by the union (polymerization) of one or more monomers with one or more acids.
Resistance - In DC circuits, the opposition a material offers to current flow, measured in ohms. In AC circuits, resistance is the real component of impedance, which may be higher than the value measured at DC.
Resonance - An AC circuit condition in which inductive and capacitive reactances interact to cause a minimum or maximum circuit impedance.
Return Loss - The ratio in decibels of the power incident upon the discontinuity to the power reflected from the discontinuity. Note: this ratio is also the square of the reciprocal of the magnitude of the reflection coefficient. Return loss = 20 log 1/p.
RF - Radio frequency.
RFI - Radio Frequency Interface.
RG/U - Symbol used to designate coaxial cables that are made to government specification (e.g., RG-58U; in this designation the "R" means radio, the "G" means guide, the "58" is the number assigned to the government approval, and the "U" means it is a universal specification).
Rigid Cable - A cable (usually large in diameter) having a heavy metal outer conductor and a center conductor supported by dielectric beads. This cable cannot be bent, which will cause the conductors to be nonconcentric and sacrifice electrical performance. Used primarily for low frequencies and high power.
Rise Time - The time required for a component or logic circuit to change from the quiescent to the transient state when an output is applied, (e.g. elapsed time between application of input and attainment of full output level).
RMS (Root Mean Square) - The effective value of an alternating current, corresponding to the direct current value that will produce the same heating effect.
Rope Strand - A conductor composed of groups of twisted strands.
Rubber (Wire Insulation) - A general term used to describe wire insulations made of thermosetting elastomers, such as natural or synthetic rubbers, neoprene, Hypalon®, butyl rubber and others.
Rupture - In the breaking strength or tensile strength tests, the point at which the material physically comes apart, as opposed to elongation yield strength, etc.
S-band - The frequency spectrum from 2 GHz to 4 GHz used for land-based microwave and some mobile satellite communications.
SAE - Society of Automotive Engineers.
Safe Working Voltage - Limit of continuous voltage for cable operation. Usually specified at 70% of Corona Extinction Voltage.
SBR - A copolymer of styrene and butadiene. Also GR-S or Buna-S. Most commonly used type of synthetic rubber.
Screening Effectiveness - Ratio of the power fed into a coaxial cable to the power transmitted by the cable through the outer conductor.
Screw Machine Contact - A contact which is machined from solid bar stock.
Self-Extinguishing - The characteristic of a material whose flame is extinguished after the igniting flame is removed.
Self-Align - Design of two mating parts so that they will engage in the proper relative position.
Semi-Flexible Cable - A cable consisting of a tin-filled braid outer conductor which will allow repeated flexure without damage. It will not hold a stable shape but is able to be hand bent.
Semi-Rigid Cable - A cable consisting of a solid metal outer conductor which may be formed into a shape which is stable. Slight flexing is possible, but repeated bending will permanently distort the outer conductor.
Semi-Rigid PVC - A hard semi-flexible polyvinylchloride compound with low plasticizer content.
Semiconductor - In wire industry terminology, a material possessing electrical conductivity that falls somewhere between that of conductors and insulators. Usually made by adding carbon particles to an insulator. Not the same as semiconductor materials such as silicon, germanium, etc. Used for making transistors and diodes.
Separator - Pertaining to wire and cable, a layer of insulating material such as textile, paper, Mylar®, etc., which is placed between a conductor and its dielectric, between a cable jacket and the components of a multiple-conductor cable. It can be utilized to improve stripped qualities, flexibility, or can offer additional mechanical or electrical protection to the components it separates.
Serve - A wrapping of wires or fibers around a central core.
Shield - (1) A conducting housing or screen that substantially reduces the effect of electric or magnetic fields on one side thereof, upon devices or circuits on the other side. Cable shields may be solid, braided or taped (longitudinally or spirally).
(2) In cables, a metallic layer placed around a conductor or group of conductors to prevent electrostatic or electromagnetic interference between the enclosed wires and external fields.
Shield Coverage - The physical area of a circuit or cable actually covered by shielding material often expressed as a percentage.
Shield Effectiveness - The relative ability of a shield to screen out undesirable interference. Frequently confused with the term Shield Coverage.
Shielding - The metal sleeve surrounding one or more of the conductors, in a wire circuit to prevent interference, interaction or current leakage.
Shock (mechanical) - (1) An abrupt impact applied to a stationary object.
(2) An abrupt or non-periodic change in position, characterized by suddenness, and by the development of substantial internal forces.
Shrink Temperature - The temperature which effects complete recovery of a shrinkable product from the expanded state.
Shrink Tubing - Tubing which has been extruded, cross-linked, and mechanically expanded which when reheated will return to its original diameter.
Shrinkage Ratio - The ratio between the expanded diameter and recovered diameter of shrinkable products.
SHV (Safe High Voltage) - Coaxial connector with bayonet coupling mechanism. Working voltage 5 kV DC.
Signal - Any visible or audible indication which can convey information. Also, the information conveyed through a communication system.
Signal Cable - A cable designed to carry current of usually less than one ampere per conductor.
Silicone® - General Electric trademark for a material made from silicone and oxygen. Can be in thermosetting elastomer or liquid form. The thermosetting elastomer form is noted for high heat resistance.
Sintering - Fusion by the use of high heat to a homogenous continuum. Usually employed for fluorocarbon, extrudable materials.
Sinusoidal - Varying in proportion to the sine of angle or time function. Ordinary alternating current is sinusoidal.
Skin Effect - The phenomenon wherein the depth of penetration of electric currents into a conductor decreases as the frequency of the current increases.
Sleeving - A braided, extruded or woven tube.
SMA (Subminiature A) - 50 ohm - subminiature coaxial connector with screw-type coupling mechanism. Frequency range DC-18 GHz.
SMB (Subminiature B) - Subminiature coaxial connector with snap-on coupling mechanism. Frequency range DC-4 GHz.
SMC (Subminiature C) - Subminiature coaxial connector with screw-type coupling mechanism. Frequency range DC-10 GHz.
SMS - Subminiature coaxial connector with slide-on coupling mechanism. Frequency range DC-4 GHz.
Snap on - Used to describe the easy removal or assembly of one part to another. A connector containing socket (female) contacts into which a plug connector having male contacts is inserted.
SNR - Signal to Noise Ratio. Commonly used interchangeably with Attentuation Crosstalk Ratio (ACR).
Solder Contact - A contact or terminal with a cup, hollow cylinder, eyelet or hood to accept a wire for a conventional soldered termination.
Soldering Sleeves - Shrinkable tubing with a solder preform used for highest reliability soldering connections or shield grounding.
Solid Conductor - A conductor consisting of a single wire.
Spark Test - A test to determine any defects in the insulation.
SPC - Acronym for silver-plated copper wire. For more information, see ASTM B-298.
SPCW - Acronym for silver-plated copper weld. However, it is actually referred to as silver-plated copper-clad steel in ASTM B-501. This wire has a steel core making up about 90% of the diameter. The remaining 10% is copper mechanically clad to the steel core with a thin silver plating over the copper.
Specific Gravity - The ratio of the density (mass per unit volume) of a material to that of water.
Spectrum - Frequencies that exist in a continuous range and have a common characteristic. A spectrum may be inclusive of many spectrums (e.g., the electromagnetic radiation spectrum includes the light spectrum, radio spectrum, infrared spectrum, etc.).
Speed of Light (c) - 2.99792458 x 108 meters per second.
Spiral Wrap - The helical wrap of material over a core.
Splice - A mechanical device or fusion process that permanently bonds two conductors together without a connector producing extremely low loss.
Spool - Circular container on which wire is wound for storage or transit, normally refers to sizes smaller than 18” in diameter.
Spring-Finger Action - Design of a contact, as used in a printed circuit connector or a socket contact, permitting easy, stress-free spring action to provide contact pressure and/or retention.
Standing Wave - The stationary pattern of waves produced by two waves of the same frequency traveling in opposite directions on the same transmission line. The existence of voltage and current maxima along a transmission line is a result of reflected energy from an impedance mismatch.
Standing Wave Ratio - A measure of the mismatch between the load the line. It is equal to 1 when the line impedance is perfectly matched to the load. (In which case the maximum and minimum are the same, as current and voltage do not vary along the line.) The perfect match would be a 1-to-1 ratio.
Static Charge - An electrical charge that is bound to an object. An unmoving electrical charge.
Static Conductor - A conductor composed of single solid wires twisted together, either singly or in groups.
STC (Supplemental Type Certificate) - Airworthiness approval issued by a governmental authority (FAA, EASA, etc.) which incorporates a modification into an aircraft’s approved configuration (Type Certificate) as safe to operate and in compliance with the airworthiness regulations.
Strain Gauge - A device for determining the amount of strain (change in dimensions) when a stress is applied.
Strand - A single uninsulated wire.
Strip Force - The force required to remove a small section of insulating material from the conductor it covers.
Stripline - A type of transmission line configuration which consists of a single narrow conductor parallel and equidistant to two parallel ground planes.
Structural Return Loss - Magnitude of the internal cable reflections, measured in decibels, relative to the actual cable impedance and not the measuring system impedance.
Substrate - Basis material on which another material is deposited, i.e. plating on Copper or Aluminum outer conductors.
Surface Resistivity - The resistance of a material between opposite sides of a unit square of its surface. It is usually expressed in ohms.
Surge - A temporary and relatively large increase in the voltage or current in an electric circuit or cable. Also called transient.
Sweep Test - Pertaining to cable, the frequency response is verified by generating an RF voltage whose frequency is swept repeatedly through a given frequency range at a rapid constant rate. The cable response is observed on a network analyzer. The structural return loss sweep-test measures the magnitude of internal cable reflections. A high structural return loss is desirable.
SWR - Standing Wave Ratio.
Tape Wrap - A spirally applied tape over an insulated or uninsulated wire.
TC (Type Certificate) - Airworthiness approval issued by a governmental authority (FAA, EASA, etc.) which confirms an aircraft is safe to operate and in compliance with the airworthiness regulations.
TDR - Time Domain Reflectometry/Time Domain Reflectometer. A measurement technique (or the instrument to perform these measurements) which allow observation of reflected waveforms from discontinuities in a transmission line. These discontinuities can be located in time or distance along the transmission line.
Tear Strength - The force required to initiate or continue a tear in a material under specified conditions.
Teflon® - DuPont Company trademark for fluorocarbon resins. See also FEP and TFE.
Tefzel® - DuPont Company trademark for high-radiation-resistant fluorocarbon (ETFE).
Temperature Rating - The maximum and minimum temperature at which an insulating material may be used in continuous operation without loss of its basic properties.
Tensile Strength - The pull stress required to break a given specimen.
Tetrafluoroethylene (TFE) - A thermoplastic material with good electrical insulation properties and chemical and heat resistance. See also PTFE.
Thermal Rating - The temperature range in which a material will perform its function without undue degradation.
Thermal Shock - The effect of heat or cold applied at such a range that non-uniform thermal expansion or contraction occurs within a given material or combination materials. The effect can cause inserts and other insulation materials to pull away from metal parts.
Thermocouple - A device for measuring temperature, at the point where two dissimilar metals are joined, and emf output is generated when heated.
Thermoplastic - A material which will soften, flow or distort appreciably when subjected to heat and pressure.
Tinned Copper - Tin coating added to copper to aid in soldering and inhibit corrosion.
Tinsel - A type of electrical conductor composed of a number of tiny threads, each thread having a fine, flat ribbon of copper or other metal closely spiralled about it. Used for small size cables requiring limpness and extra-long flex life.
TNC (Threaded Neill Concelman) - Coaxial connector with screw-type coupling mechanism. Available in 50 ohm and 75 ohm versions. Frequency range DC-11 GHz (50 ohm) and DC-1 GHz (75 ohm), respectively.
Tolerance - A specified allowance for error from a standard or given dimension, weight or property.
Topology - The architecture of a network or the way circuits are connected to link the network nodes together.
Transducer - A device for converting mechanical energy to electrical energy.
Transfer Impedance - For a specified cable length, transfer impedance relates to a current on one surface of a shield to the voltage drop generated by this current on the opposite surface of the shield. Transfer impedance is used to determine shield effectiveness at lower frequencies (<1 GHz) against both ingress and egress of interfering signals. Cable shields are normally designed to reduce the transfer of interference–hence, shields with lower transfer impedance are more effective than shields with higher transfer impedance.
Transformer - A device for converting AC current from one voltage to another either “stepped up” or “stepped down.”
Transmission Line - A signal-carrying circuit composed of conductors and dielectric material with controlled electrical characteristics used for the transmission of high-frequency, narrow-pulse type signals.
Transmission Line Cable - Two or more conductors placed within a dielectric material in such a way as to control the electrical characteristics.
Transmission Loss - The decrease or loss in power during transmission of energy from one point or another. Usually expressed in decibels.
Triaxial - Refers to three conductor cables with one conductor in the center, a second circular conductor concentric with the first and third circular conductor insulated from the concentric with the first and second, usually with insulation and a braid or impervious sheath overall.
Triaxial Cable - A cable consisting of one center conductor and two outer concentric conductors (with an insulating layer separating them). Notable for increased shielding efficiency.
Triboelectric Noise - Noise generated in a shielded cable due to variation in capacitance between the shield and conductor as the cable is flexed.
Tubing - A tube of extruded non-supported plastic or metallic material.
Twinaxial Cable - Two conductors that are insulated from each other, twisted together and surrounded by a common shield.
Twinning - Synonymous with pairing.
UG - Symbol used to describe coaxial connectors that were made to a government specification. This specification is now obsolete.
UHF Connector - Coaxial connector with screw-type coupling mechanism. Non-defined impedance. Frequency range DC to 300 MHz. Also known as a PL-259 Connector.
Ultra High Frequency (UHF) - A Federal Communications Commission designation for the band from 300 MHz to 3,000 MGz (3 GHz) on the radio spectrum.
Unbalanced Line - A transmission line in which voltages on the two conductors are unequal with respect to ground (e.g., a coaxial cable).
Unilay - A conductor with more than one layer of helically laid wires with the direction of lay and length of lay the same for all layers.
V - Symbol for volt.
VA (Volt Ampere) - A designation of power in terms of voltage and current.
Velocity of Propagation - The transmission speed of electromagnetic energy in a length of cable compared to speed in free space. Usually expressed as a percentage.
Very High Frequency (VHF) - A Federal Communications Commission designation for the band from 30 to 300 MHz in the radio spectrum.
Video - Pertaining to picture information in a television system.
Viton - DuPont trademark for a series of fluoroelastomers based on the copolymer of unylidene fluoride and hexafluoropropylene.
VLF (Very Low Frequency) - The spectrum extending from 10 kHz to 30 kHz, as designated by the Federal Communications Commission (FCC).
Volt - A unit of electrical pressure. One volt is the electrical pressure that will cause one ampere of current to flow through one ohm of resistance.
Voltage - The term most often used to designate electrical pressure that exists between two points and is capable of producing a flow of current when a closed circuit is connected between the two points. Voltage is measured in volts, millivolts, microvolts and kilovolts. The terms electromotive force (emf), potential, potential difference and voltage drop are often referred to as voltage.
Voltage Drop - The voltage developed across a component or conductor by the current flow through the resistance or impedance of the component or conductor.
Voltage Rating - The highest voltage that may be continuously applied to a wire in conformance with standards or specifications.
Voltage Standing Wave Ratio (VSWR) - A measure of the reflection, resulting from a ratio of the input signal to the reflected signal.
Volume Resistivity - The electrical resistance between opposite faces of a one centimeter cube of insulating material, commonly expressed in ohms-centimeter.
VSWR - See Voltage Standing Wave Ratio and Standing Wave Ratio.
W - Symbol for watt or wattage.
Water Absorption - Water by percent weight absorbed by a material after a given immersion period.
Watt (W) - A unit of electrical power. One watt is equivalent to the power represented by one ampere of current with a pressure of one volt in a DC circuit.
Waveform - 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.
Waveguide - Hollow pipe (round or rectangular) used as transmission line for the propagation of microwaves.
Wavelength - 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. Increasing the frequency of the pulse or waveform shortens its wavelength.
Wetting - The ability of liquid solder to attach itself to the surfaces being joined through the formation of intermatallic bonds.
Wicking - The longitudinal flow of a liquid in a wire cable due to capillary action.
Wiping Action - The action which occurs when contacts are mated with a sliding action. Wiping has the effect of removing small amounts of contamination from the contact surfaces, thus establishing better conductivity.
Wire - A slender rod of metal usually referring to a single conductor, bare or insulated, #9 AWG and smaller.
Wireless - Using the radio-frequency spectrum for transmitting and receiving voice, data and video signals for communications.