Glossary

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tab: (terminal) Used to describe the flat blade portion of certain terminals (eg a FASTON* tab, a taper tab, a solder tab).; Also, on strip terminals, is used to describe the projection which results when the point-of-shear is not flush with the terminal body (ie cutoff tab).
table: (general) A collection of data in tabular form (usually in parallel rows or columns for ready reference), with each item being uniquely identified by some label or by its relative position. See also truth table.
Tab-Lok crimp: (terminal) A type of crimp used on FASTON flag terminals whereby a tab on the wire barrel is inserted through a slot in the terminal. The crimping action flattens the tab between two lances, which in turn are locked over the tab.
tap: (network) The means of connecting a piece of equipment to the transmission media of a network.
tape-mounted: (terminal) Screw-machine or pre-insulated terminals (or contacts) that are produced in loose-piece form and then inserted into plastic pockets in continuous lengths, and placed on reels, for application in automatic or semi automatic machines.
taper pin: (contact) A small conical shaped electrical contact that utilizes the Morse taper principle to effect a strong mechanical connection after being impacted into a receptacle of corresponding geometric form.
target area: (tooling/terminal) A term used to indicate the relationship of the three axes (lateral, vertical, and axial) of terminal with the crimp tooling. The point at which all three axes coincide is called the target area.
TC: Tray Cable. Multi-conductor cable specifically approved for use installed in cable trays.
tcr: (abbreviation) Temperature coefficient of resistance.
TDM: (abbreviation) See time-division multiplexing.
telecommunication: (circuit/system) Any process that enables a correspondent to pass to one or more given correspondents (telegraphy or telephony), or possible correspondents (broadcasting), information of any nature delivered in any usable form (written or printed matter, fixed or moving, pictures, words, music, visible or audible signals, signals controlling the functioning of mechanisms, etc) by means of any electromagnetic system (electrical transmission by wire, radio transmission, optical transmission, etc, or a combination of such systems).
temperature coefficient: (circuit) A factor used to calculate the change in the characteristics of a substance, device, or circuit element with changes in its temperature. The values are usually expressed as a percentage per degree Celsius. Applies to the change in capacitance or resistance of any electronic part or element per degree change in temperature.
temperature coefficient of linear expansion: (measurement) The amount of change in any linear dimension of a solid arising from a change in temperature. Usually measured in microinches per inch per degree Celsius. When crimping two metals with dissimilar coefficients, ie, aluminum wire in a copper terminal wire barrel, special considerations must be included in the terminal design to prevent deterioration from “creep.” See also creep.
Temperature Rating: The maximum and minimum temperature at which an insulating material may be used in continuous operation without loss of its basic properties.
temperature requirement: This would involve both the upper- and low-end temperatures required for the product or environment.
temperature rise: (terminal) Change in temperature of a terminal from a no-load condition to full-current load. Also called T rise.
tensile: (terminal) The amount of axial load (longitudinal stress) required to break or pull the wire from the crimped barrel of a terminal, splice, or contact. Also called “pull test.”
Tensile Strength: The greatest longitudinal stress that a substance or union can bear without tearing or pulling apart. In crimped terminations, it is the greatest longitudinal stress that a terminal can bear without the wire separating from the terminal.
terminal: (component) An electrically conductive item designed to be attached to a circuit or device for convenience in making electrical connections.
terminal area: (circuit) The portion of a printed circuit – usually along the edge – used for making the input-output connections. Sometimes this term is used synonymously with pad. See also land, and pad.
terminal barrel: (terminal) See barrel.
terminal strip: (component) An insulated mounting for terminal connections. Terminal strips are available with threaded holes to accept threaded screws, or with threaded studs to accept fastening washers and nuts. If the terminal areas are separated by an insulating barrier, the terminal strips are called barrier blocks.
terminus: (fiber optic) A part of a fiber-optic connector analogous to a contact.
terpolymer: (material/process) A resin formed by three separate monomers polymerized together.
thermal compression bond: (process) The joining of metals by the combined effects of temperature and pressure.
thermal expansion: (coefficient of) (property) The fractional change in length (sometimes volume) of a material for a unit of change in temperature.
thermal rating: (property) The maximum and/or minimum temperature at which a material will perform its function without undue degradation.
Thermal Shock: The effect of heat or cold applied at such a rate that non-uniform thermal expansion or contraction occurs within a given material or combination of materials. The effect can cause inserts and other insulation materials to pull away from metal parts.
thermal time-delay switch: (component) An over current-protective device containing a heater element and thermal delay.
thermoplastic: (material) A type of plastic which can be re-melted a number of times without any important change in properties. Nylon and polyvinyl-chloride (pvc) are examples of thermoplastics. Such plastics are resilient after molding.
thermoplastic elastomer: (tpe) (material) A jacket material which has many of the characteristics of rubber, as well as excellent electrical, mechanical, and chemical properties.
thermosetting plastic: (material) A type of plastic in which an irreversible chemical reaction takes place while it is being molded under heat and pressure. This type of plastic cannot be reheated or softened. Phenolic and diallyl phthalate are examples of thermosetting plastics.
Thermoset: A material that hardens or sets when heat is applied and that, once set, cannot be re-softened by heating. The application of heat cures or vulcanizes the material.
thick film circuit: (IC) A circuit fabricated by deposition of materials forming passive components and conductors to an approximate thickness 0.05 mils on a non-conducting substrate (generally alumina or beryllia).
thin film circuit: (IC) A circuit fabricated by deposition of materials in a vacuum to form passive components and conductors to a thickness of several hundred angstroms on an insulating substrate.
Time-Delay: A Circuit that delays the transmission of an impulse for a definite and desired period of time.
time-delay relay: (component) A relay in which the energizing or de-energizing of the coil precedes movement of the armature by an appreciable – and generally determinable – interval.
time-delay switch: (component) A switch having contacts which control a load circuit and are delayed from operating for a predetermined time interval.
tinning: (process) A hot dip process for the application of solder coating on conductors and terminals primarily for minimizing in-process oxidation and enhancing solder ability.
TNC Series connector: (connector) A radio frequency connector covered by Military Specification. It has an impedance of 50 ohms and is designed to operate in the 0 to 11 GHz frequency range. Reliability is assured by a threaded coupling that can be safety wired to prevent accidental disconnect.
TO can: (component) Transistor outline. A standard system for specifying the dimensions of a transistor package. Each different package is given a number: TO-5, TO-18, TO-52, etc.
tolerance: (general) The allowable variations in measurements within which an item is judged acceptable.
toroid: (circuit/system) A coil or transformer wound on a donut shaped core. The toroidal core gives a maximum magnetic field within itself, with minimum magnetic flux leakage externally.
TPE: Abbreviation for Thermoplastic elastomer.
Topology: The architecture of a network, or the way circuits are connected to link the network nodes together.
tracking: (electrical) The action of a high voltage current creating a leakage or fault path across the surface of insulation by steadily forming a carbonized thin line between electrodes.
Transceiver: A device used in contention networks for sending data over the network and receiving data from the network.
transfer molding: (process) A method of molding thermosetting materials, in which the plastic is first softened by heat and pressure in a transfer chamber, and then forced into a closed mold for final curing.
transients: (electrical) Undesirable voltage and current surges that are usually caused by capacitive or inductive energy discharges in electrical circuits.
transistance: (property) An electronic characteristic exhibited in the form of voltage or current gain, or in the ability to control voltages or currents in a precise nonlinear manner. Transistors, diodes, and vacuum tubes are examples of components which show transistance.
transistor: (component) An active solid-state semiconductor device with three or more electrodes and capable of amplification, rectification, and switching. Important features are low power, small size, and long life. Two main types are bipolar and field effect.
TRAPATT: (abbreviation) TRApped Plasma Avalanche Transit Time.
triac: (component) A multi layer semiconductor device designed for ac power supply applications. It presents an open circuit between its two power terminals to ac until it is triggered on. It then has a low forward voltage drop like an SCR. The triggering pulse, applied to the triggering terminal, can be of either polarity during either half cycle of applied voltage. Planar triacs have been fabricated.
trimming: (process/IC) The adjustment of resistor or capacitor values in thick or thin film circuits by pattern changes, irreversible thermally induced changes, or removal of portions of material by laser or abrasive techniques. Dynamic trim is unique to these technologies, and of great value to circuit design and manufacture.
Trunk Cable: Trunk Cable typically refers to a copper twisted pair backbone or vertical riser cable consisting of multiple groups of 25 pairs.
Twisted Pair: Two wires twisted together to reduce susceptibility to RF noise.
two-piece connector: (connector) A board-to-board connector in which part of the connector is attached to each board.
two-piece contact: (contact) See contact, two-piece.

Glossary

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