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 RadioShack Consumer Electronics Glossary: T

 
T-: see Tera (T-).
 
T-1 Carrier
Telephony, Internet: A dedicated telephone line that consists of 24 separate channels. Each channel supports a data rate of 64 Kbps, and the entire T-1 supports data rates of 1.544 Mbps. Each channel can be configured separately.
 
T-3 Carrier
Telephony, Internet: A dedicated telephone line that consists of 672 separate channels. Each channel supports a data rate of 64 Kbps, and the entire T-3 supports data rates of 43 Mbps. Each channel can be configured separately.
 
Tachometer
Test Equipment: An instrument designed to measure the rate of rotation.
 
Talk Time
Telephony: The length of time a user can talk on a cordless telephone or portable or transportable cellular telephone without recharging the battery.
 
Tantalum Capacitor: see Capacitor, Tantalum.
 
Tagged Image File Format: see TIFF.
 
TAO
Acronym: Track At Once
Computers: A CD burning process that can write tracks individually, up to 99 total. Automatically places 2 second gaps between tracks.
 
Target
Digital Video: The object or field of view being photographed.
Metal Detectors: An object sensed by the detector.
 
Target ID
Metal Detectors: The identification of detected metal objects.
 
Target Masking
Metal Detectors: The effect of large pieces or high concentrations of trash metals driving the threshold into the null zone, that hides or masks weaker responses from deeper or smaller targets.
 
Target Response: see Signal.
 
Tc
Measurement: Case temperature.
 
TCP/IP
Acronym: Transmission Control Protocol / Internet Protocol
Internet: The communications protocols used to connect host systems on the Internet.
 
TDMA
Acronym: Time Division Multiple Access
Telephony: A transmission system that provides the ability to transmit multiple voice circuits per channel. A TDMA channel is a single FDMA channel divided into multiple time slots.
 
tebi- ( Ti-)
Measurement, Computers: New SI / Metric unit of binary measurement, not yet fully adopted, equal to 240 or 1, 099, 511, 627, 776.
 
Telecommunications
Telephony: The science of transmitting signals representing voice, video, or data over telephone lines.
 
Telecommunications Industry Association: see TIA.
 
Telephony
Telephony: A telecommunications system involving the transmission of speech information, such as but not limited to corded and cordless home telephones and cellular telephones.
 
Telephoto
Digital Video: A lens with a focal length that gives you the narrowest angle of coverage, good for bringing distant objects closer.
 
Temperature
Weather: A severe thunderstorm characterized by a rotating, long-lived, intense updraft. Although not very common, they produce a relatively large amount of severe weather, in particular, extremely large hail, damaging straight-line winds, and practically all violent tornadoes.
 
Temperature
Weather: The measure of molecular motion or the degree of heat of a substance. It is measured on an arbitrary scale from absolute zero, where the molecules theoretically stop moving. It is also the degree of hotness or coldness. In surface observations, it refers primarily to the free air or ambient temperature close to the surface of the earth.
 
Temperature, Absolute
Weather: A temperature scale with a freezing point of +273³K (Kelvin) and a boiling point of +373³K.
 
Temperature, Mean
Weather: The average of temperature readings taken over a specified amount of time. Often the average of the maximum and minimum temperatures.
 
Temporary Mobile Station Identifier: see TMSI.
 
Ten-Turn
Metal Detectors: A control that can be manually rotated ten times to cover the full electrical range of the function. Usually associated with tuning or ground balance function.
 
tera- ( T-)
Measurement: SI / Metric unit of decimal measurement, equal to 1012 or 1,000,000,000,000.
Measurement, Computers: Unit of binary measurement, equal to 240 or 1, 099, 511, 627, 776.
 
Terminal
Electronics: The point on a cell or component where an electrical connection is made.
 
Terminal Block: see Terminal Strip.
 
Terminal Node Controller: see TNC.
 
Terminal Strip
Electronics: A connector that has screw posts separated by insulating barrier strips. Also called Terminal Block or Barrier Strip Connector.
 
Terminator: see Resistor, Terminating.
 
Terminating Resistor: see Resistor, Terminating.
 
Test Garden
Metal Detectors: A mapped plot of buried targets at various depths to aid in learning characteristic target responses and in comparing metal detector performances under a given ground mineral content. Also called Test Plot or Test Bed.
 
TFT
Acronym: Thin Film Transistor
Digital Video: The type of high resolution color LCD screen used in many digital photography cameras.
 
TGT. SEL.
Acronym: Target Select
Metal Detectors: A mode of operation that allows certain metals to be selectively accepted or rejected.
 
tGQ
Measurement: Turn-off time.
 
THD
Acronym: Total Harmonic Distortion
Audio, Electronics: The property of an audio signal that is equal to the ratio of the sum of the powers of all harmonics above the fundamental, or lowest, frequency to the power of the fundamental frequency.
 
Thermal Dye Sublimation: see Dye Sub.
 
Thermistor
Electronics: Temperature sensitive semiconductor that has a negative temperature coefficient of resistance. As temperature increases, resistance decreases.
 
Thermo Autochrome Printer
Computers: A printer technology that uses paper with three heat-sensitive pigment layers (cyan, magenta, and yellow) in the paper, that are activated and fixed using ultraviolet light.
 
Thermocouple
Electronics: A temperature transducer consisting of two dissimilar metals welded together at one end to form a junction that when heated will generate a voltage.
 
Thermometer
Weather: An instrument used for measuring temperature. The different scales used in meteorology are Celsius, Fahrenheit, and Kelvin or absolute.
 
Thermometer, Dry Bulb
Weather: A thermometer used to measure the ambient temperature. The temperature recorded is considered identical to air temperature. One of the two thermometers that make up a psychrometer.
 
Thermometer, Resistance
Weather:A new type of temperature measurement that uses electronics to determine the temperature by measuring the change in resistance across a material such as germanium or platinum.
 
Thermometer, Wet Bulb
Weather: A thermometer used to measure the lowest temperature in the ambient atmosphere in its natural state by evaporating water from a wet muslin-covered bulb of a thermometer. The wet bulb temperature is used to compute dew point and relative humidity. One of the two thermometers that make up a psychrometer.
 
Thermosphere
Weather: A thermal classification, it is the layer of the atmosphere located between the mesosphere and outer space. It is a region of steadily increasing temperature with altitude, and includes all of the exosphere and most, if not all, of the ionosphere.
 
Thiele-Small Parameters
Audio: A set of parameters used to describe the audio characteristics of a speaker driver, named for Neville Thiele and Richard Small. The ten original Thiele-Small parameters are Fs, Pe, Qes, Qms, Qts, Re, Sd, Xmax, Vas, and Vd. The parameters Xmag and Xsus have been added to this list.
 
Thin Film Transistor: see TFT.
 
Thinnet: see 10Base-2.
 
Threshold
Metal Detectors: A continuous tone that establishes a reference point for tuning the detector in order to ground balance it. The threshold tone also establishes the minimum sound level for deep targets in the discriminate mode.
 
Threshold Tone
Metal Detectors: A barely audible tone set by the tuner control.
 
Threshold Voltage: see Voltage, Threshold.
 
Through The Lens: see TTL (Digital Video).
 
Thumbnail
Digital Video: A small, low resolution version of a larger image file that is used for quick identification.
 
Thunder
Weather: The sound emitted by rapidly expanding gases along the channel of a lightning discharge. Over three-quarters of lightning's electrical discharge is used in heating the gases in the atmosphere in and immediately around the visible channel. Temperatures can rise to over 10,000 °C in microseconds, resulting in a violent pressure wave, composed of compression and rarefaction. The rumble of thunder is created as one's ear catches other parts of the discharge, the part of the lightning flash nearest registering first, then the parts further away.
 
Thunderstorm
Weather: A storm produced by a cumulonimbus cloud, it is a microscale event of relatively short duration characterized by thunder, lightning, gusty surface winds, turbulence, hail, icing, precipitation, moderate to extreme up and downdrafts, and under the most severe conditions, tornadoes.
 
Thunderstorm, Severe
Weather: A thunderstorm with winds measuring 50 knots (58 mph) or greater, 3/4 inch hail or larger, or tornadoes. Severe thunderstorms may also produce torrential rain and frequent lightning.
 
Thyristor
Electronics: A four-layer semiconductor device, such as an SCR or triac.
 
THX
Acronym: THX is not an acronym; it takes its name from "THX 1138", George Lucas' first feature film.
Audio: A multi-channel surround sound system. For specific details on THX audio, we recommend the THX website.
 
Ti-: see Tebi (Ti-).
 
TIA
Acronym: Telecommunications Industry Association
Telephony: A trade association for the communications and information technology industry, responsible for developing telecommunications standards.
 
TIFF
Acronym: Tagged Image File Format
Digital Video: A lossless uncompressed image file format that does not produce artifacts (such as are common with lossy image formats such as JPG).
 
Tilt
Satellite: The degree of circular rotation on a satellite dish.
 
Time Division Multiple Access: see TDMA.
 
Time-Lapse
Digital Video: A video capture method that captures a series of images at preset intervals.
 
Tj
Measurement: Junction temperature ( TjM unless otherwise indicated).
 
TjM
Measurement: Maximum junction temperature.
 
TMSI
Acronym: Temporary Mobile Station Identifier
Telephony: A mobile station identifier (MSID) dynamically assigned to the mobile station by the network and sent over the air interface. See also MIN, IMSI.
 
TNC
Acronym (Communications): Terminal Node Controller
Acronym (Cables): Threaded Neill-Concelman (after inventors Paul Neill & Carl Concelman)
Communications: A dedicated microprocessor system for use with amateur radio packet data communications.
Cables: A threaded BNC connector (click here for an illustration).
 
 
Toggle Switch: see Switch, Toggle.
 
Token Ring
Computers, Networking: A type of network with a ring topology in which information is carried via a special bit pattern (or token).
 
Tolerance
Electronics: The maximum deviation permitted from a specified value, normally expressed as a percentage or as +/- a given number.
 
Tonearm
Audio, Turntables: The long "arm" that holds the headshell, cartridge, stylus and counterweight.
 
Tone ID
Metal Detectors: Circuitry producing different audio tones for each target's conductivity range -- for example, a low tone for nickel, and a high tone for coins. Also called Audio ID.
 
TO Package
Acronym: Transistor Outline Package
Electronics: A semiconductor component package that is a cylindrical metal can.
 
Topology
Computers, Networking: The geometric layout of a network. See also Bus, Ring, Star, Mesh, Tree.
 
Tornado
Weather: A violently rotating column of air in contact with and extending between a convective cloud and the surface of the earth. It is the most destructive of all storm-scale atmospheric phenomena. They can occur anywhere in the world given the right conditions, but are most frequent in the United States in an area bounded by the Rockies on the west and the Appalachians in the east.
 
Tornado Alley
Weather: A geographic corridor in the United States which stretches north from Texas to Nebraska and Iowa. In terms of sheer numbers, this section of the United States receives more tornadoes than any other.
 
Toroid
Electronics: A coil of insulated or enameled wire wrapped onto a donut-shaped powdered iron core, used as an inductor.
 
Total Harmonic Distortion: see THD.
 
Touch-tone
Telephony: Telephones that are dialed using a keypad to produce DTMF tones. Technically, only rotary telephones are "dialed", but the term has become part of common vocabulary.
 
Towering Cumulus: see Cumulus, Towering.
 
TPDDI
Acronym: Twisted Pair Data Distribution Interface
Networking: an FDDI which uses twisted-pair cable to transport information instead of fiber-optic cable.
 
TR
Acronym: Transmitter / Receiver
Metal Detectors: A term used to describe an early type of detector, still produced by some manufacturers. Electromagnetic field distortion caused by mineralized ground interferes with depth penetration because this type of detector does not ground compensate; however, it does balance salt water effects. Because of this, it is primarily used for searching in salt water and on low-mineral salt water beaches.
 
Track At Once: see TAO.
 
Tracking Force
Audio, Turntable: The amount of force that the cartridge exerts on the record's surface.
 
Transceiver
Communications: A transmitter and a receiver combined in a single package.
 
Transceiver
Plug 'n Power: A device that receives commands from a remote transmitter (controller) and transmits X-10 signals through electrical wiring to a receiver (module).
 
Transducer
Electronics: A device that converts energy from one form to another.
 
Transformer
DIY, Electronics: An inductor with two or more windings. The main winding is the primary; additional windings are the secondaries. A transformer uses mutual inductance from the primary winding to induce current into the secondary windings.
 
Transformer, Center-tapped
Electronics: A transformer with a tap (electrical connection) at the electrical center of a winding.
 
Transformer, Class #
Electronics: There are three classses of power transformer. These classes are set in the National Electrical Code, ANSI/NFPA 70 and are identified by the circuit class they are designed for.
Class 1 Transformer Class 1 Circuit
Class 2 Transformer Class 2 Circuit
Class 3 Transformer Class 3 Circuit
 
Transformer, Step-down
Electronics: A transformer that converts the input AC voltage to a lower AC voltage (such as a 240V to 120V transformer).
 
Transformer, Step-up
Electronics: A transformer that converts the input AC voltage to a higher AC voltage (such as a 120V to 240V transformer).
 
Transistor
Acronym: Transfer Resistor
DIY, Electronics: A semiconductor device with a base, an emitter and a collector, that can be used either as an amplifier or as an electronic switch.
 
Transistor, NPN
Electronics: A bipolar junction transistor that has a p-type base and an n-type emitter and collector.
 
Transistor, PNP
Electronics: A bipolar junction transistor that has an n-type base and a p-type emitter and collector.
 
Transistor-Transistor Logic: see TTL (Electronics).
 
Transit Screws
Audio, Turntable: Screws permanently mounted in a turntable in order to, when tightened, secure the platter and other moving parts for transport.
 
Transmitter
Communications, Plug 'n Power: A device that sends a wireless signal that can be picked up and utilized by a corresponding receiver.
 
Transponder
Satellite: A "channel" on a satellite with a specific bandwidth and uplink/downlink frequency.
 
Transportable
Telephony: A cellular car telephone with the handset, antenna, and battery packaged together in a carrying case. While these telephones are portable and mobile, the name transportable use used to differentiate these telephones from small, handheld one-piece wireless cellular telephones. See Mobile.
 
Trash Metals:
Metal Detectors: Metals that you are not looking for and/or that interfere with finding what you are looking for.
 
Tree
Computers, Networking: A network topology in which the computers are connected as illustrated below. See also Bus, Ring, Star, Mesh.
 
Triac
Electronics: A bidirectional gate-controlled thyristor similar to an SCR, but capable of conducting in both directions and provides full wave control of AC power.
 
Trickle Charge: see Standby Charge.
 
Trimpot: see Potentiometer, Trimmer.
 
Trimmer
Electronics: A small-value variable capacitor, variable resistor (potentiometer) or variable inductor that is used to fine-tune a circuit. See Potentiometer, Trimmer.
 
Triple-conversion
Communications: A demodulation method that uses a three-stage receive circuit with three intermediate frequencies to extract the data signal from the carrier.
 
Tropopause
Weather: The boundary zone or transition layer between the troposphere and the stratosphere. This is characterized by little or no increase or decrease in temperature or change in lapse rate with increasing altitude.
 
Troposphere
Weather: The lowest layer of the atmosphere located between the earth's surface to approximately 11 miles (17 kilometers) into the atmosphere. Characterized by clouds and weather, temperature generally decreases with increasing altitude.
 
True Color
Digital Video: Color with a depth of 24-bits and 16.7 million colors.
 
True RMS
DIY: Refers to a multimeter that calculates the correct RMS value, rather than rectifying the waveform and applying a correction factor (based on a sine wave) to an average measured value. True RMS meters provide the correct value regardless of the waveform; meters that do not provide True RMS measurement are only accurate when measuring sinusoidal waveforms.
 
Trunktracking
Communications: Following conversations that are broadcast on two-way radios automatically tuned by a computer. Also called Trunking or Trunked Scanning.
 
TTL
Acronym (Digital Video): Through The Lens
Acronym (Electronics): Transistor-Transistor Logic
Digital Video: An autofocus or autoexposure system that works through the camera's lens.
Electronics: A DTL logic gate that replaces the input diodes with transistors. The 7400 family of digital ICs are TTL devices.
 
Tuner
Audio, Communications: A radio receiver that simply receives and does not amplify the signal.
 
Turns Ratio
DIY, Electronics: The ratio of secondary winding turns to primary winding turns of a transformer.
 
Turntable
Audio, Turntable: An analog audio device that converts the data encoded in the grooves of a record into an audio signal.
 
Turntable, Belt-drive
Audio, Turntable: A turntable in which there is a motor, a pulley and a belt that goes from the pulley to either the outer edge or inner rim of the platter. Belt-driven turntables are quieter than those that are direct-driven.
 
Turntable, Direct-drive
Audio, Turntable: A turntable in which the platter is turned by the spindle, which is directly attached to the motor.
 
TWAIN
Acronym: "TWAIN" is not an acronym. For addition information, see the TWAIN Working Group's website.
Digital Video, Computers: A protocol for exchanging information between applications and devices such as scanners and digital cameras. Often, when a digital camera installs and does not work, uninstalling and reinstalling the TWAIN drivers can resolve the problem.
 
Tweeter
Audio: A speaker driver designed to reproduce the higher frequencies.
 
Twin-Ax
Acronym: Twin-Axial
Cables: A cable similar to coax, but with two internal conductors rather than one, both of which are surrounded by a common shield.
 
Twisted Pair
Cables: A cable consisting of two wires twisted around each other, with each wire having it's own insulation. One wire carries the signal while the other wire is grounded and absorbs signal interference. There are presently eight categories (abbreviated CAT) of twisted pair cable systems: CAT 1, CAT 2, CAT 3, CAT 4, CAT 5, CAT 5E, CAT 6, and CAT 7. The categories are differentiated by the maximum data rate (measured in Mbps or MHz) and the type of application. Data Rate
MHz / Mbps
Category Application
CAT 1 <1 analog voice (POTS)
ISDN
Doorbell wiring
CAT 2 4 Token Ring networks
CAT 3 16 Voice and data on 10BASE-T Ethernet
CAT 4 20 16 Mbps Token Ring
CAT 5 100
1000 (4 pair)
100 Mbps TPDDI
155 Mbps ATM
Gigabit Ethernet
CAT 5E 100 100 Mbps TPDDI
155 Mbps ATM
CAT 6 <400 Super-fast Broadband Applications
CAT 7 600-700
 
Twisted Pair Data Distribution Interface: see TPDDI.
 
TX
Audio, Communications: shorthand for Transmit or Transmitting.
 
Type I, II, III
Digital Audio, Digital Video, Computers, Telephony: Refers to particular PCMCIA or PC Card storage devices, differentiated by thickness.
  • Type I: up to 3.3 mm thick
  • Type II: up to 5.5 mm thick
  • Type III: up to 10.5 mm thick

Type I and II fit in the single-height card slots, Type III only fit in the double-height slots.


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