Glossary

F

F crimp: (process/terminal) A crimp that brings the center of the barrel along an open seam downward into a V.
Face: (connector) See interface (connector).
Face seal: (connector) See interfacial seal.
Failure mechanism: (quality/reliability) A structural or chemical defect which causes failure such as corrosion, poor bonds, or surface inversion.
Fan in: (circuit) The number of logic inputs into a logic gate.
Fan out: (circuit) The number of logic inputs that can be driven by the output of a logic gate.
Farad: Unit of capacitance whereby a charge of one coulomb produces a one volt potential difference.
Fatigue: (metal) The tendency of a metal to fracture in a brittle manner under conditions of repeated cyclic stressing at stress levels below its tensile strength.
FDDI: Fiber Distributed Data Interface. A standard for a 100 megabit-per-second local area network.
Feedback: (circuit) The recycling of a portion of an output to the input of the circuit.
Positive feedback: Recycling of a signal that is in phase with the input to increase amplification. Used in digital circuits to standardize the waveforms in spite of any anomalies in the input.
Negative feedback: Recycling of a signal that is 180° out of phase with the input to decrease amplification. Used in linear circuits to stabilize performance and minimize distortion.
Feed through: (component) A connector or terminal block, usually having double ended terminals which permit 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.
Feed-through capacitor: (component) A feedthrough insulator that provides a desired value of capacitance between the feedthrough conductor and the metal panel or chassis through which the conductor is passing. Often used in bringing dc power into a shielded enclosure.
Feed-through connection: (circuit) Use interfacial connection.
FEP: (abbreviation) Fluorinated ethylene propylene.
Ferrule: (connector/component) A short tube. Used to make solderless connections to shielded or coaxial cable. Also molded into the plastic inserts of multiple contact connectors to provide strong, wear-resistant shoulders on which contact retaining springs can bear. The basis for alignment in many AMP fiber-optic connectors.
FET: (abbreviation/component) Field-effect transistor. A transistor controlled by voltage rather than current. The flow of working current through a semiconductor channel is switched and regulated by the effect of an electric field exerted by electric charge in a region close to the channel called the gate.
FET resistor: (component) In many MOSFET digital circuits, all components can be of a source-gate-drain structure. By adjusting the topology of the structure (and its location in the circuit) it may be considered primarily a resistor or capacitor or transistor. An FET resistor is an FET in which the gate is generally tied to the drain and used instead of a resistor load for an FET transistor.
FFC: (abbreviation/component) Flexible flat cable; flat flexible cable; or flexible flat conductor. A form of multiple conductor cable consisting of parallel flat metal strips imbedded in a flat flexible insulating material.
Fiber optics: (technology) A technology in which light is transmitted through an optical fiber. Most often used as a transmission link connecting two electronic circuits.
Field: A region containing electric or magnetic lines of force, or both.
Filled cable: (communication) 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 multi-conductor cables to occupy large interstices formed by the assembled conductors. (2) An inert substance added to a compound to improve properties or decrease cost. (material) Fairly inert, low-cost substances added to plastic compounds to reduce cost or improve stiffness.
Film: (electrical) An adherent layer of a foreign substance on a contact surface.
Filter: (component) A network of resistance, capacitance, and inductance designed to pass certain frequencies and attenuate all others. The main types are low pass, high pass, band pass, and band reject.
Fishpaper: (material) A type of fiber paper used for insulating purposes where high mechanical strength is required.
Flag terminal: (component) A type of terminal having the tongue or body project at 90_ from the side of the terminal barrel, rather than being in line with – and extending from – the end of the barrel.
Flame Resistance: The ability of a material not to propagate flame once the heat source is removed.
Flame retardants: (material) Either reactive compounds or additive compounds added to formulation to increase resistance to combustion. Reactive fire-retardant compounds become an integral part of the polymer structure, while additive fire-retardant chemicals are physically dispersed in the polymer.
Flammability: (property) Measure of the material’s ability to support combustion.
Flange: (connector) A projection extending from – or around the periphery of – a connector, and having holes that provide for mounting the connector to a panel, or to a mating connector.
Flash: (quality/reliability) A thin film of material formed at the sides of a forging, casting or molded part where some of the material is forced between the faces of the forging dies or the mold halves. Also, the excess metal extruded between both halves of crimping dies when making certain circumferential or symmetrical crimps. Also would include a thin deposit of plastic material usually at the base of molded-in pins.
Flex Life: The measurement of the ability of a conductor or cable to withstand repeated bending.
Flexibility: Ability of cable to bend in a short radius. The quality of a cable that allows for bending under normal circumstances.
Flexibilizer: (material) An additive that makes a resin or rubber more flexible. More commonly called plasticizer.
Flexible substrate: (material/component) Thick and thin film circuits have generally been deposited on rigid substrates, but it is possible to deposit these circuits on plastic substrates such as Kapton or Mylar which are flexible. Kapton and Mylar are trademarks.
Floating bushing: (connector/accessory) A design feature which aids in the alignment of plug and receptacle shells during a rack and panel type of engagement. The floating bushing is generally an eyelet-type bushing which is fitted and retained in the plug mounting holes. Even though mounting screws are passed through the bushings and fastened to a frame, the plug is still permitted freedom of motion in all directions in seeking out the mating receptacle.
Floating ground: (electrical) A grounding technique in which circuit grounds (return paths) are isolated from earth ground.
Flow Soldering: (process) See wave soldering. Flow Soldering is a trade name for specific wave soldering equipment manufactured by a company in England.
Fluorocarbons: (material) Organic hydrocarbons in which one or more hydrogen atoms of the organic backbone have been replaced with fluorine atoms.
Fluoroplastics: (material) Polymers made of monomers which contain one or more atoms of fluorine.
Flux: (material) A material used to remove oxide films and promote fusion or joining of metals in soldering, brazing, or welding.
FM: (frequency modulation) (circuit) A method of transmission in which the frequency of the carrier is varied in accordance to the signal.
4/8 indent crimp: (terminal) A military-approved crimp used on screw-machined pin and socket contacts, such as in AMPLIMITE* connectors. The crimp consists of either one or two rows of indents equally spaced around the wire barrel of the contact.
Frame: (connector) The surrounding portion (usually metal) of a multiple contact connector having a removable module or insert. The frame supports the insert and provides a method for mounting the connector to a panel or a mating connector. See also shell.
Free hanging: (connector) A connector that is movable and not fixed to a board, panel, or frame. It will mate with another free-hanging connector or with a panel mount connector.
Free standing: (terminal) A contact/terminal installed on a pc board and used without a housing.
Frequency (f): (measurement) The number of complete cycles per unit of time – used for periodic quantities such as alternating current, sound waves, or vibrating objects. The number of times an alternating current repeats its cycle in one second. Frequency is generally expressed in hertz (cycles per second), kilohertz, megahertz, or gigahertz.
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: (circuit/system) The measure of how the gain or loss of a circuit, device, or system varies with frequency. Also called frequency characteristic, amplitude- frequency response, response, response characteristic, and sine-wave response.
Frequency Voice: (communication) A frequency lying within that part of the audio range which is employed for speech transmission.
Note: Frequencies used for commercial transmission of speech usually lie within the range 200 to 3500 hertz (cps).
Fretting corrosion: (general) A form of accelerated oxidation that occurs at the interface of contacting materials undergoing slight, cyclic relative motion. All non-noble metals (tin) are susceptible to some degree and will suffer contact resistance increases.
Front-mounted: (connector) A connector is said to be 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.
Funnel entry: (product feature) Flared or widened entrance to a terminal or contact wire barrel. Permits easier insertion of the conductor, and helps assure that all wire strands will be directed into the wire barrel.

Glossary

F

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