| T-1 A leased-line connection capable of carrying data at 1,544,000 bits-per-second. At maximum theoretical capacity, a T-1 line could move a megabyte in less than 10 seconds. That is still not fast enough for full-screen, full-motion video, for which you need at least 10,000,000 bits-per-second. T-1 lines are commonly used to connect large LANs to theInternet. |
| T-3 A leased-line connection capable of carrying data at 44,736,000 bits-per-second. This is more than enough to do full-screen, full-motion video. |
| T1 (Carrier System): A digital communications link that operates at 1.544 Mb/s in North America and Japan. The European version is called E1 and operates at 2.048 Mb/s.
|
| T2 Carrier System: A North American digital communications link that is formed by multiplexing three T1 systems and operates at 6.312 Mb/s. The European version is E2. |
| T3 Carrier System: A North American digital communications link that is formed by multiplexing seven T2 systems and operates at 47.736 Mb/s. The European version is E3.
|
| Taper Charge: A charge regime delivering moderately high rate charging current when the battery is at a low state of charge and tapering the charging current to lower rates as the battery is charged.
|
| Target Size Effect: See Size-of-Source Effect. |
| Tau: The third flavour of charged lepton (in order of increasing mass), with electric charge -1. |
| TCP/IP: Transmission Control Protocol/Internet Protocol. This is a common shorthand which refers to the suite of application and transport protocols which run over IP. These include FTP, Telnet, SMTP, and UDP (a transport layer protocol).
|
| TDM: Time Division Multiplexing.
|
| Telemetry: Transmission and collection of data obtained by sensing conditions in a realtime environment. |
| Telephony-Grade: 99.9994% uptime or the higher reliability standard circuit switches require (translating into 3 minutes of downtime a year), as opposed to the "carrier-class" reliability standard of 99.999% (called "five-nines").
|
| TELNET: The Internet standard protocol for remote terminal connection service. Telnet allows a user at one site to interact with a remote timesharing system at another site as if the user?s terminal was connected directly to the remote computer.
|
| TEMPCO: Abbreviation for "temperature coefficient": the error introduced by a change in temperature. Normally expressed in %/?C or ppm/?C.
|
| Temperature Compensation: The utilization of supplementary devices, materials, or components within the bridge to minimize sources of error caused by changing temperature.
|
| Temperature Derating: The amount by which power source or component ratings are decreased to permit operation at elevated temperatures.
|
| Temperature Effect On Span: The change in rated output due to a change in ambient temperature. Usually expressed as +/- a percentage change in rated output per degree F change in ambient temperature over the compensated temperature range.
|
| Temperature Effect On Zero: The change in zero balance due to a change in ambient temperature. Usually expressed as +/- a percentage change in rated output per degree F change in ambient temperature over the compensated temperature range.
|
| Temperature Error: The maximum change in output, at any measurand value within the specified range, when the transducer temperature is changed from room temperature to specified temperature extremes.
|
| Temperature Resolution: The minimum simulated or actual change in target temperature that gives a usable change in output and/or indication.
|
| Temperature, Compensated: The range of temperature over which a transducer can operate up to full scale and still meet all specifications.
|
| Temperature, Operating: The range of temperature over which a transducer may be safely operated up to full scale without causing failure, but specifications may not be met.
|
| Temporal Drift: The change in accuracy of an instrument over time. This effect may be due to aging of the instrument?s components or calibration changes. |
| Terminal A device that allows you to send commands to a computer somewhere else. At a minimum, this usually means a keyboard and a display screen and some simple circuitry. Usually you will use terminal software in a personal computer - the software pretends to be (emulates) a physical terminal and allows you to type commands to a computer somewhere else.
|
| Terminal Server: A special purpose computer that has places to plug in many modemson one side, and a connection to a LAN or host machine onthe other side. Thus the terminal server does the work of answering thecalls and passes the connections on to the appropriate node. Most terminal servers can provide PPP or SLIP services if connectedto the Internet. |
| Terminal: An input/output device used to enter data into a computer and record the output.
|
| Ternary Alloy: |
| Tertiary Winding: A third winding on a transformer.
|
| Tesla (T): SI unit of magnetic flux density (magnetic induction) expressed as 1 weber/square meter.
|
| Test Gas: Test Gas is a known concentration of the gas to be detected diluted with clean air. |
| Thermal Coefficient of Resistance: The change in resistance of a semiconductor per unit change in temperature over a specific range of temperature.
|
| Thermal Conductivity: The property of a material to conduct heat in the form of thermal energy.
|
| Thermal Desorber: Describes the primary treatment unit that heats petroleum-contaminated materials and desorbs the organic materials into a purge gas or off-gas.
|
| Thermal Equilibrium: The point at which the temperature of a component or device becomes stable.
|
| Thermal Expansion: An increase in size due to an increase in temperature expressed in units of an increase in length or increase in size per degree, i.e. inches/inch/degree C.
|
| Thermal Gradient: The distribution of a differential temperature through a body or across a surface.
|
| Thermal Mass: Material that stores energy, although mass will also retain coolness. The thermal storage capacity of a material is a measure of the materials ability to absorb and store heat. |
| Thermal Protection: A protective feature that shuts down a power supply if its internal temperature exceeds a predetermined limit.
|
| Thermal Runaway: A condition. in a power source or component where an increase in temperature increases current flow causing a further increase in temperature, the spiraling effect of which leads to failure.
|
| Thermal Sensitivity Coefficient: The difference between the electrical output at temperature T 1 and temperature T 2 with full range applied pressure, as expressed by % F.R.O./?C or % F.R.O./?F.
|
| Thermal Sensitivity Shift: The sensitivity shift due to changes of the ambient temperature from room temperature to the specified limits of the compensated temperature range.
|
| Thermal Shock: Stresses induced in a material because of a rapid temperature change or a thermal gradient.
|
| Thermal Zero Coefficient: The difference between the electrical output at temperature T 1 and temperature T 2 with zero applied pressure, as expressed by % .R.O./?C or % F.R.O./?F.
|
| Thermal Zero Shift: An error due to changes in ambient temperature in which the zero pressure output shifts. Thus, the entire calibration curve moves in a parallel displacement.
|
| Thermistor: A temperature-sensing element composed of sintered semiconductor material which exhibits a large change in resistance proportional to a small change in temperature. Thermistors usually have negative temperature coefficients.
|
| Thermocouple: The junction of two dissimilar metals which has a voltage output proportional to the difference in temperature between the hot junction and the lead wires (cold junction) (refer to Seebeck emf).
|
| Thermophotovoltaic Cell: A device where sunlight concentrated onto a absorber heats it to a high temperature, and the thermal radiation emitted by the absorber is used as the energy source for a photovoltaic cell that is designed to maximize conversion efficiency at the wavelength of the thermal radiation. |
| Thermopile: An arrangement of thermocouples in series such that alternate junctions are at the measuring temperature and the reference temperature. This arrangement amplifies the thermoelectric voltage. Thermopiles are usually used as infrared detectors in radiation pyrometry.
|
| Thermowell: A closed-end tube designed to protect temperature sensors from harsh environments, high pressure, and flows. They can be installed into a system by pipe thread or welded flange and are usually made of corrosion-resistant metal or ceramic material depending upon the application. |
| Thomson Effect: When current flows through a conductor within a thermal gradient, a reversible absorption or evolution of heat will occur in the conductor at the gradient boundaries.
|
| Threading and Knurling: A method of surface roughening in which spiral threads are prepared, followed by upsetting with a knurling tool. |
| Three-phase Current: Alternating current in which three separate pulses are present, identical in frequency and voltage, but separated 120 degrees in phase.
|
| Threshold Limit Value Time-Weighted Aver Threshold Limit Value Time-Weighted Average (TLV-TWA) is the time-weighted average concentration of a substance for a normal 8-hour work day and a 40-hour work week, to which nearly all workers may be repeatedly exposed, day after day. (OSHA) |
| Thyristor: A solid state device that has bistable electrical characteristics. Three common thyristor devices are diacs, silicon-controlled-rectifiers (SCRs) and triacs.
|
| Time Constant: Time period required for the voltage of a capacitor in an RC circuit to increase to 63.2 percent of maximum value or decrease to 36.7 percent of maximum value.
|
| Time Stamp: Information added to a unit of data to indicate the time at which it was processed. |
| TNT equivalent: The weight of TNT which would release the same amount of energy as a particular nuclear explosion. One ton of TNT releases approximately 1.2 billion calories (that is, 5.1 kiloJoules per gram). Nuclear explosions are usually measured in kilotons (KT) or megatons (MT).
|
| Token Passing: A protocol that gives a terminal permission to transmit on a Token Ring LAN. A unique bit pattern, called a token, circulates around the ring from terminal to terminal. The terminal that possesses the token has permission to transmit.
|
| Token Ring: A LAN standard, also known as IEE 802.5, that connects a ring topology. Token Ring LANs operate at 4 Mb/s or 16 Mb/s.
|
| Top Quark (t): The sixth flavour of quark (in order of increasing mass), with electric charge 2/3. Its mass is much greater than any other quark or lepton. |
| Topping-cycle: A means to increase the thermal efficiency of a steam electric generating system by increasing temperatures and interposing a device, such as a gas turbine, between the heat source and the conventional steam-turbine generator to convert some of the additional heat energy into electricity.
|
| Total Harmonic Distortion: The measure of closeness in shape between a waveform and it`s fundamental component.
|
| Total Regulation Band: The range of combined regulation tolerances such as the effects of input voltage variation, output load variation, temperature variation, drift and other specified variables. It is expressed as a plus/minus percent from nominal. Also called accuracy limits.
|
| Total Thermal Error: The maximum sensitivity and zero error, caused by temperature, within the compensated temperature range.
|
| Toughness: A measure of the energy absorbed before and during the fracture process; it is equal to the area under the tensile stress-strain curve.
|
| TQM: Total Quality Management.
|
| Trace: A conducting path on a printed circuit board. |
| Tracking Regulator: A plus and minus two-output supply in which one output tracks the other.
|
| Traction Battery: A secondary battery designed for the propulsion of electric vehicles or electrically operated mobile equipment operating in a deep-cycle regime.
|
| Train Lighting Battery: A secondary battery used in trains to maintain essential services such as lighting and air conditioning.
|
| Transceiver: A combined transmitter and receiver. |
| Transconductance: The ratio of the incremental change in the output current of an amplifier to the incremental change of input voltage. |
| Transducer Vibration: Generally, any device which converts movement, either shock or steady state vibration, into an electrical signal proportional to the movement; a sensor.
|
| Transducer: A device (or medium) that converts energy from one form to another. The term is generally applied to devices that take physical phenomenon (pressure, temperature, humidity, flow, etc.) and convert it to an electrical signal.
|
| Transient Effect: The result of a step change in an influence quantity on the steady state values of a circuit.
|
| Transient Recovery Time: The time required for the output voltage of a power supply to settle within specified output accuracy limits following a transient.
|
| Transient Response Time: The interval between the time a transient is introduced and the time it returns and remains within a specified amplitude range.
|
| Transient Response: Ability of a power supply to recover a constant voltage following a step change in output current.
|
| Transient Vibration: A temporary vibration or movement of a mechanical system. |
| Transient: An excursion in a given parameter, typically associated with input voltage or output loading.
|
| Transistor: Transistors are the basic elements in integrated circuits. A transistor is an electric switch with no moving parts that is turned on and off by applying an electric signal.
|
| Transitional Flow: Flow between laminar and turbulent flow, usually between a pipe Reynolds number of 2000 and 4000.
|
| Transmitter: A transducer that has a 4-20 mA two wire output.
|
| Transponder: Batteryless electronic code memory which transmits and receives low frequency messages upon activation by an external electromagnetic field.
|
| Transverse Sensitivity: Signal output as a result of acceleration perpendicular to the sensitive axis. Specified as a percentage of sensitive axis output for equivalent right angle acceleration or as a decimal fraction.
|
| Triac: A solid state switching device used to switch alternating current wave forms. |
| Trickle Charge: A charge at low rate, balancing losses through local action and/or periodic discharge, to maintain a cell or battery in a fully charged condition.
|
| Triclinic: Having three axes of any length with none of the included angles being equal to one another or 90 degrees.
|
| Trigger An external stimulus that initiates one or more instrument functions. |
| Trigger Jitter The short-term variation of the time period between a trigger event and the first sample point.
|
| Trigger Latency The fixed time offset between the trigger event and the first sample point. |
| Triple Point (Water): The thermodynamic state where all three phases, solid, liquid, and gas may all be present in equilibrium. The triple point of water is .01?C.
|
| Triple Point: The temperature and pressure at which solid, liquid, and gas phases of a given substance are all present simultaneously in varying amounts |
| Tritium: A radioactive isotope of hydrogen whose nucleus contains one proton and two neutrons.
|
| Trombe Wall: A wall with high thermal mass used to store solar energy passively in a solar home. The wall absorbs solar energy and transfers it to the space behind the wall by means of radiation and by convection currents moving through spaces under, in front of, and on top of the wall.
|
| True RMS: The true root-mean-square value of an AC or AC-plus-DC signal, often used to determine power of a signal. For a perfect sine wave, the RMS value is 1.11072 times the rectified average value, which is utilized for low-cost metering. For significantly non-sinusoidal signals, a true RMS converter is required.
|
| TTL Unit Load: A load with TTL voltage levels, which will draw 40 ?A for a logic 1 and -1.6 mA for a logic 0.
|
| TTL-Compatible: For digital input circuits, a logic 1 is obtained for inputs of 2.0 to 5.5 V which can source 40 ?A, and a logic 0 is obtained for inputs of 0 to 0.8 V which can sink 1.6 mA. For digital output signals, a logic 1 is represented by 2.4 to 5.5 V with a current source capability of at least 400 ?A; and a logic 0 is represented by 0 to 0.6 V with a current sink capability of at least 16 mA.
|
| TTL: Transistor-to-transistor logic. A form of solid state logic which uses only transistors to form the logic gates.
|
| Tukon Hardness Test: A method for determining microhardness by using a Knoop diamond indenter or Vickers square-base pyramid indenter.
|
| Tuned Circuit: Circuit containing capacitance, inductance and (optionally) resistance, connected in series or parallel, which when energized at a specific frequency known as its resonant frequency, an inter-change of energy occurs between the coil and the capacitor.
|
| Turbidity: Suspended matter in water or wastewater that scatters or otherwise interferes with the passage of light through the water.
|
| Turbulent Flow: When forces due to inertia are more significant than forces due to viscosity. This typically occurs with a Reynolds number in excess of 4000.
|
| Turns Ratio: Ratio of the number of turns on the primary winding of a transformer to the number of turns on the secondary winding.
|
| TWAIN Scanner Interface API: Technology Without An Interesting Name |
| Twisted Pair: Two insulated wires, usually made from copper, that are twisted in a regular, six turns per inch spiral pattern used to connect most telephones. Also used as a medium by several local area networks. |
| Two Stage Gas Booster Haskel A booster that has two (2) pumping sections of different ratios operating with a single air drive. These sections are normally at opposite ends of the air drive. There is usyally a "lower" ratio, high volume end on the inlet stage for maximum displacement, and a "higher" ratio low volume on the 2nd stage for generating final presssure |
| Two-Color Thermometry: A technique that measures the energy in two different wavelength bands (colors) in order to determine temperature. The 2 color technique has been shown to be effective for correcting errors due to partial blockage of the target caused by dust particles. |
| Typical: Error is within plus or minus one standard deviation (?1%) of the nominal specified value, as computed from the total population.
|
Additions/Suggestions/Assistance
