Glossary of Terms
| Term | Definition |
|---|---|
| T rise | Change in temperature of a terminal from a no-load condition to full-current load. |
| T1 | Digital transmission facility operating with a nominal bandwidth of 1.544 Mbps. Also known as Digital Signal Level 1 (D1). Composed of 24 DS-0 channels in many cases. The T1 digital transmission system if the primary digital communication system in North America. |
| T2L | Transistor Transistor Logic. A popular bipolar logic family based on a multiple-emitter transistor. Compared to MOS logic, TTL is generally faster, although it uses more power and offers less packaging density. See also Schottky TTL. Also called TTL |
| T3 | Digital transmision facility operating at 45 Mbps bandwidth. Composed of 28 DS-1 channels in many cases. Also known as DS-3. |
| T568A and B | The two standard wiring patterns for 8-position modular jacks. |
| tab | 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 | 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 | 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. |
| tactile feedback | The feel or snap action of certain constructions of keyboards. |
| tap (network) | The means of connecting a piece of equipment to the transmission media of a network. |
| Tap loss | In a fiber-optic coupler, the ratio of power at the tap port to the power at the input port. |
| Tap port | In a coupler in which the splitting ratio between output ports is not equal, the output port containing the lesser power. |
| tape memory | A serial, bulk-storage, off-line memory medium consisting of metal, paper, or plastic tape coated with magnetic material. Information is stored as small magnetized spots, usually arranged in columns across the width of the tape, with each column representing a tape character. A read-write head is usually associated with each row of magnetized spots so that one column can be read or written at a time as the tape is moved relative to the head. Paper tape in which data is stored in form of punched holes, as in numerically controlled machinery and teletype equipment, is also considered tape memory. |
| Tape Wound Core | Cores made by rolling strips of alloy iron into a toroidal shape. The metal strips have a precisely controlled thickness which are coted with a very thin insulation material to prevent the metal in the layers to make contact with each other. The finished cores have an outside coating to protect the metal layers and they are offered in a variety of material mixes. Tape wound cores are capable of storing high amounts of energy and contain a high permeability. Their major disadvantage is that they are relatively expensive when compared to other core types (Also see Toroidal Inductor) |
| Tape Wound Cores | Cores made by rolling strips of alloy iron into a toroidal shape. The metal strips have a precisely controlled thickness, which are coated with a very thin insulating material to prevent the metal in the layers to make contact with each other. The finished cores have an outside coating to protect the metal layers and they are offered in a variety of material mixes. Tape wound cores are capable of storing high amounts of energy and contain a high permeability. Their major disadvantage is that they are relatively expensive when compared to other core types. |
| Tape Wrap | A term denoting a spirally or longitudinally applied tape material wrapped around insulated or uninsulated wire and used as a mechanical barrier. |
| tape-mounted | 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 | 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 | 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 | (1) Tinned copper; (2) Temperature Coefficient - 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. |
| tcr | Temperature coefficient of resistance. |
| TDM | Time-division multiplexing. |
| TDMA | Time division multiple access. A transmission in which a frequency band is split into a number of time slots so that several callers can share a single channel without interfering with each other. The term TDMA is commonly used to denote the IS -136 air interface standard, formerly known as D-AMPS. |
| TDMA | Time Division Multiple Access. (See also CDMA) |
| TDOP | Time clock offset |
| Tear Test | A test to determine the tear strength of an insulating material. Usually includes exposure to given thermal conditions or a programmed series of conditions for prescribed periods of time. |
| Technischer Uberwachungs-Verin (TUV) | Organization approved for testing products to VDE standards. US-based companies often use TUV in place of VDE because they hae established facilities in the US. |
| Tee coupler | A three-port optical coupler. |
| Telco | Short for telecommunications (or telephone company). |
| Telco connector | Refers to a 25-pair (AMP CHAMP) connector. |
| Telecom closet | Telecommunications closet. The area of the building that houses the termination of the horizontal cabling.May also contain LAN electronics. Also called wiring closet |
| telecommunication | 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). |
| Telecommunications Transformers | Also referred to as broadband transformers, these are transformers specialized for connecting a piece of equipment to the phone line or telephone network. Its function is to isolate the equipment from the phone line, improve common mode noise rejection, and match different impedances. |
| Telecommuter | Person who performs work at home while linked to the office by means of a telecommunications-equipped computer system. |
| telpak | A high-speed telephone or broadband service. Telpak has the wide band channels necessary for computer-to-computer communication and other special high-speed applications. There are presently four sizes of telpak available: Telpak A - Equivalent in capacity to 12-voice circuits.; Telpak B - Equivalent in capacity to 24-voice circuits.; Telpak C - Equivalent in capacity to 60-voice circuits.; Telpak D - Equivalent in capacity to 240-voice circuits. |
| temperature coefficient | TC - 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 Inductance | (Tc of L)Is the value of inductance change as a function of temperature exposure, normally expressed in parts per million per degrees Celsius. This is a calculation comparing inductance at a reference temperature (25 degrees C, room ambient) to the extremes and other temperatures within operating range. Can be called Percent Delta L. or Temperature Stability: the lower the change the better for most applications. |
| temperature coefficient of linear expansion | 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 Factor (TF) | The fractional change in initial permeability over a temperature range divided by the initial permeability. |
| Temperature Range | The ambient temperature range of the air (or other medium) surrounding a PolySwitch device under normal operating conditions. |
| Temperature Rating | The maximum temperature at which the insulating material may be used in continuous operation without loss of its basic properties. Usually time dependent. |
| temperature rise | (1) Change in temperature of a terminal from a no-load condition to full-current load. Also called T rise. (2) The increase in surface temperature of a component in air due to the power dissipation in the component. The power dissipation for an inductor includes both copper and core losses. |
| Tempest | A classified Department of Defense program to provide secure electronic equipment through extensive EMC techniques. |
| tensile | 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 (union) can bear without tearing (pulling) apart. In crimped terminations: the greatest longitudinal stress that the termination can bear without the wire and terminal separating. |
| tera | A prefix indicating 1012, a trillion, abbreviated "T." |
| Terahertz | A frequency of, or a frequency in the range of a trillion hertz. Abbreviated THz. |
| Terapin | A trillion pins. |
| Termal Conductivity | Given materials ability to conduct heat, which is the time rate for heat transfer (via conduction) across a unit material thickness of 1 meter and when the temperature differential of the two opposite faces is 1 degree K. |
| terminal | An electrically conductive item designed to be attached to a circuit or device for convenience in making electrical connections. |
| terminal area | 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 | See barrel. |
| terminal strip | 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. |
| Termination | A one port component that terminates a transmission line. |
| terminus | A part of a fiber-optic connector analagous to a contact. |
| terpolymer | A resin formed by three separate monomers polymerized together. |
| Tesla | The MKSA (SI) unit for magnetic flux density, defined by Faraday's Law. A Tesla represents a volt-second per square meter per turn. One Tesla is equal to 10,000 Gauss. |
| Test Frequency | Is the industry/military standard for testing a range of inductances. It is not intended as the application frequency. Expressed in megahertz (MHz) or kilohertz (KHz) |
| TETRA-CRIMP tools | Exclusive AMP designed tooling featuring a trapezoidal crimp configuration which will crimp PIDG and PLASTI-GRIP terminals and splices, as well as PIDG and PLASTI-GRIP FASTON receptacles all in the same tool. Includes hand tool, crimping dies, and applicators. |
| thermal compression bond | The joining of metals by the combined effects of temperature and pressure. |
| Thermal Conductivity | Given materials ability to conduct heat, which is the time rate for heat transfer (via conduction) across a unit material thickness of 1 meter and when the temperature differential of the two opposite faces is 1 degree K. |
| Thermal Derating | The change in the hold current and trip current of a PolySwitch device that takes place as there is a change in the ambient temperature of the air (or other medium) surrounding the device. An increase in ambient temperature decreases the hold current (and the trip current). A decrease in ambient temperature increases the trip current (and the hold current). |
| thermal expansion | The fractional change in length (sometimes volume) of a material for a unit of change in temperature. |
| Thermal Gasket | Flexible pad or wafer with a very low thermal resistance that is put between a power module baseplate and heat sink to ensure high thermal conductivity across the junction |
| Thermal Joint Compound | A fluid or paste spread between the mating surfaces of a power device baseplate and a heat sink or system chassis. |
| Thermal noise | Noise resulting from thermally induced random fluctuation in current in the receiver's load resistance. |
| Thermal Protection | Feature that shuts the converter down if the internal tempurature exceeds preset limits. Also called thermal shutdown. |
| Thermal Rating | The effect of heat or cold applied at such a rate that nonuniform thermal expansion or contraction occurs within a given material or combination of materials. In electrical terminations, the effect can cause inserts and other insulation material to pull away from the metal parts. |
| thermal rating | The maximum and/or minimum temperature at which a material will perform its function without undue degradation. |
| Thermal Resistance | The property of a material, device or system that impedes the flow of heat. The symbol for thermal impedance is Qxy , where x is the physical point from which heat flows and y is the physical point to which heat flows. Thermal impedance is defined as the temperature difference between two specified points or regions divided by the power dissipation under conditions of thermal equilibrium. |
| Thermal Resistivity | Measure of a material;s ability to impede the flow of heat. Typically given in degrees C T/W, where T is the material thickness and W is the power flowing through the material in watts. |
| thermal shock | The effect of heat or cold applied at such a rate that nonuniform 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 Shock Test | A test in which the resistance of a PolySwitch device at room temperature is measured before and after a temperature cycling treatment (e.g., cycled 10 times between Ð55¡C and +125¡C). |
| thermal timedelay switch | An overcurrent-protective device containing a heater element and thermal delay. |
| Thermochromic Indicator | Special compound that changes color when the proper wetting temperature has been reached in the solder joint. |
| Thermoplastic | A material that softens (melts and flows) when heated and becomes firm when cooled. A type of plastic that can be remelted a number of times without any important change in properties. Nylon, GE’s Lexan, and PVC—examples of this type of plastic—are resilient after molding. |
| thermoplastic elastomer | tpe - A jacket material which has many of the characteristics of rubber, as well as excellent electrical, mechanical, and chemical properties. |
| Thermoset | A material that hardens or sets when heated and, once set, cannot be resoftened by heating. This application of heat is called “curing.” |
| Thermosetting Adhesive | A curing adhesive that requires heat to promote curing. This type of plastic will not soften when reheated. See Epoxy. |
| thermosetting plastic | 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. |
| Thick Film | A film of material that was silk-screened onto a substrate. |
| thick film circuit | A circuit fabricated by deposition of materials forming passive components and conductors to an approximate thickness 0.05 mils on a nonconducting substrate (generally alumina or beryllia). |
| Thicknet | IEEE 10BASE5.10 Mbps Ethernet on thick coaxial cable. |
| Thin Film | A film of material, ranging in thickness from a few hundred to a few thousand Angstroms, which is deposited by evaporation onto a substrate. |
| thin film circuit | 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. |
| Thinnet | IEEE 10BASE2. 10 Mbps Ethernet on thin (RG58) coaxial cable. |
| Three-Terminal Regulator | Regulator packaged in a standard 3-terminal transistor package. These devices can be a switching type or a linear shunt or series regulator. |
| Throughput loss | In a fiber-optic coupler, the ratio of power at the throughput port to the power at the input port. |
| Throughput port | In a coupler in which the splitting ratio between output ports is not equal, the ouput port containing the greater power. |
| Thyristor | Commonly used to protect telecom equipment, data transmission lines and signal lines, Thyristor devices fold back from high to low resistance when responding to a voltage surge. |
| time-delay | A circuit that delays the transmission of an impulse a definite and desired period of time. |
| time-delay relay | A relay in which the energizing or deenergizing of the coil precedes movement of the armature by an appreciable - and generally determinable - interval. |
| time-delay switch | A switch having contacts which control a load circuit and are delayed from operating for a predetermined time interval. |
| time-division multiplexing | A technique used in data communications technique for combining several lower speed channels into one transmission path at higher speed in which each low-speed channel is allotted a specific position based upon time in the signal stream. |
| timeshare | To use a device for two or more interleaved purposes. |
| Time-to-Trip | The time needed, from the onset of a fault current, to trip a PolySwitch device. For any particular type of PolySwitch device, trip time depends upon the size of the fault current and the ambient temperature. The higher the fault current and/or the higher the temperature, the shorter the trip time. |
| tinning | A hot dip process for the application of solder coating on conductors and terminals primarily for minimizing in-process oxidation and enhancing solderability. |
| TNC Series 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 | 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. |
| Token ring | A networking protocol based on a token-passing ring. |
| Tolerance | The total amount by which a quantity is allowed to vary from nominal; thus, the tolerance is half the algebraic difference between the maximum and minimum limits. |
| tone-encoded keyboard | A keyboard encoded in rows and columns designed to be the same as those used in telephones. |
| Toroid | A core that has a donut shaped surface. Toroidal cores are available in many magnetic core materials. Characteristics of toroidal inductors include self-shielding due to a closed magnetic path, efficient energy transfer, high coupling between windings, and early saturation. The toroidal core gives a maximum magnetic field within itself, with minimum magnetic flux leakage externally. |
| Toroidal Inductor | An inductor constructed by placing a winding(s) on a core that has a donut shaped surface. Toroidal cores are available in many magnetic core materials within the four basic types: Ferrite, Powdered iron, Alloy and High Flux, and Tape Wound. Characteristics of toroidal inductors include: self shielding (closed magnetic path), efficient energy transfer, high coupling between windings and early saturation. |
| Trace Capacitance | The capacitance between trace to reference plane |
| Traceability | The ability to trace the history, application, or location of an item and like items or activities by means of recorded identification. The lot number/manufacturing order (MO) number, or SMO number used to identify items or groups of items is traceable back to inspection and procurement records. |
| track | The portion of a moving storage medium, such as a drum, tape, disc, or card, that contains the encoded data. |
| tracking | 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. |
| Tracking | For a multiple output converter the parameter that gives the change in one output voltage caused by a change in the voltage level or load on another output. |
| transfer molding | 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. |
| Transformer | A passive device that changes voltage, current, or impedance to the required parameters. This is usually done by placing two or more windings around a soft magnetic core. Applying a voltage to the primary winding will produce a magnetic field in the core, and in turn induce a voltage in the secondary winding(s). |
| Transient | Spike or step change in a converter paramenter. Commonly used in describing input line and output load characteristics. |
| Transient Recovery Time | Time required for a converter output to return to within specified limits following a step change in output load current. Expressed as a percentage of rated value. |
| Transient Suppression | The use of special devices to minimize the effects of transients in electronic circuits. Transient suppression devices include the metal oxide varistor (MOV), semiconductor transient voltage suppressor (TVS) and gas tube. |
| transients | Undesirable voltage and current surges that are usually caused by capacitive or inductive energy discharges in electrical circuits. |
| transistance | 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 | 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. |
| Transition Time | The time required for a varactor or step recovery diode to change from the conducting to non-conducting state after reverse bias is applied, excluding the time required for charge to be conducted from the junction. It is normally measured from the 90 percent to 10 percent reverse current states. Transition time is also called "snap time." |
| Transmission Cable | Two or more transmission lines. If the structure is flat, it is sometimes called flat transmission cable to differentiate it from a round structure such as a jacketed group of coaxial cables. See also Transmission Line. |
| Transmission Control Protocol/Internet Protocol (TCP/IP) | A reliable, full duplex, connection-oriented end to end transport protocol running on top of IP. |
| Transmission Line | A signal-carrying circuit with controlled electrical characteristics; used to transmit high-frequency or narrowpulse signals. |
| Transparent LAN Service | Service offered by a provider that is used to connect LANs at geographically separated sites. "Transparent" means the connection is invisible to the user and typically runs at the same speed as the LANs. |
| TRAPATT | TRApped Plasma Avalanche Transit Time. |
| TRI | telephony return interface |
| triac | A multilayer 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. |
| Triaxial Cable | A concentrically constructed cable, with a common axis, composed of a center connector, first shield, and second shield, all insulated from each other. |
| trimming | 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. |
| Trip | Switching of a PolySwitch device from a low resistance to a high resistance. In its low-resistance state, the device permits normal currents to flow in a circuit. Occurrence of a fault drives the device to its high-resistance (or 'tripped') state, and this reduces the current in the circuit to a low level. |
| Trip Current | The smallest steady state current that, if passed through a PolySwitch device, will cause the device to trip, under specified conditions. |
| Trip Cycle | The tripping and resetting of a PolySwitch device under specified conditions. |
| Trip Cycle Life | The number of trip cycles that a PolySwitch device will undergo without failure, with failure being defined in a specified way. |
| Trip Time | The time needed, from the onset of a fault current, to trip a PolySwitch device. For any particular type of PolySwitch device, trip time depends upon the size of the fault current and the ambient temperature. The higher the fault current and/or the higher the temperature, the shorter the trip time. |
| Tri-State | Tri-State buffer is a buffer that can be either input or output |
| TRK | Track. Direction of travel relative to a ground position (same as Course Over Ground) |
| TRN | Turn. The degrees which must be added to or subtracted from the current heading to reach the course to the intended waypoint. |
| truth table | A table that defines a logic function by listing all combinations of input values, and indicating for each combination the true output values. |
| TTFF | Time to First Fix |
| TTL | Transistor-transistor logic. A popular bipolar logic family based on a multiple-emitter transistor. Compared to MOS logic, TTL is generally faster, although it uses more power and offers less packaging density. See also Schottky TTL. Also called T2L |
| TtT | The time needed, from the onset of a fault current, to trip a PolySwitch device. For any particular type of PolySwitch device, trip time depends upon the size of the fault current and the ambient temperature. The higher the fault current and/or the higher the temperature, the shorter the trip time. |
| Tuning Monotonicity | The degree to which the sign of the slope of the tuning response versus stimulus curve of a device does not change. |
| Tunnel Diode | A heavily doped p-n diode in which electron tunneling from the conduction band in the n-type material to the valence band in the p-type region produces a region of negative resistance. Tunnel diodes may be used as oscillators, amplifiers or detectors (M/A-COM does not manufacture tunnel diodes). |
| Turn Ratio | The ratio of the primary voltage (or turns) to the secondary voltage (or turns) |
| Twisted Pair | Cable consisting of two 18 to 24 AWG (American Wire Gauge) solid copper strands twisted around each other. The twisting provides a measure of protection from electromagnetic and radio-frequency interference. |
| Twisted pair cable | Cable made from pairs of wires which have been twisted together. |
| two-piece 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. |
| Two-tone Third-Order Intermodulation Distortion | The intermodulation distortion products produced by a component or system when two distinct signals at frequencies f1 and f2 are incident on the device. The third order products are defined as 2*f1-f2 and 2*f2 - f1. These products fall very near the original frequencies and are difficult or impossible to remove by filtering, so they are most troublesome to the operation of the system or component. |
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