The Illustrated Dictionary of Electronics - Loscha

television • temperature derating 677television 1. Abbreviation, TV. The transmissionand/or reception, via electromagnetic fields, wirecable, and/or fiberoptic cable, of images, usuallywith sound. 2. A system for receiving signals, asdefined in 1. 3. Video programs or data, with orwithout sound, transmitted via electromagneticfields, wire cable, and/or fiberoptic cable.television band See UHF TELEVISION CHANNELSand VHF TELEVISION CHANNELS.television camera The pickup device that scans ascene and delivers a series of electrical signalsthat can be used to reconstruct the image on thescreen of a picture tube.television-camera tube See CAMERA TUBE,ICONOSCOPE, and ORTHICON.television channel A radio-frequency band allocatedexclusively for the transmission of a televisionsignal. In conventional broadcasting, thisband is usually 6 MHz wide. See, specifically,UHF TELEVISION CHANNELS and VHF TELEVI-SION CHANNELS.television engineer A trained professional skilledin video electronics engineering, as well as in basicengineering and associated subjects.television engineering The branch of electronicsengineering devoted to the theory and applicationof television.television interference Abbreviation, TVI. Interferenceto the reception of television signals, usuallyoccasioned by signals from radio services orcomputers, or by electrical noise.televisor 1. A television transmitter or receiver.2. A person or entity responsible for the broadcastof television programs or signals.televoltmeter A TELEMETER for measuring voltagegenerated at a remote point.telewriter See TELAUTOGRAPH.Telex 1. A teleprinter system that operates via thetelephone lines, and was once commonly used bybusinesses for sending and receiving short messages.It has largely been supplanted by computerizeddata communications systems. 2. A hard-copymessage sent or received by such a system.telluric currents Also called terrestrial currents.A flow of electrical charge carriers, primarily electrons,in the earth.tellurium Symbol, Te. A rare, metalloidal elementrelated to selenium. Atomic number, 52. Atomicweight, 127.60.TE mode See TRANSVERSE ELECTRIC MODE.temp 1. Abbreviation of temperature. (Also, T.)2. Abbreviation of temporary. 3. Abbreviation ofTEMPLATE.temperament The tuning of a keyboard-type musicalinstrument to produce a nearly perfect diatonicscale.temperature Symbol, T. A quantitative measure ofthe heat exhibited by an object or phenomenon.Also see THERMOMETER SCALE.temperature coefficient A figure that states theextent to which a quantity drifts or varies underthe influence of changing temperature. It is generallyexpressed in percent per degree (%/°C) orin parts per million per degree (ppm/°C).temperature-compensated crystal oscillationOscillation in a crystal oscillator, in which thecrystal and/or circuit is automatically compensatedagainst frequency drift caused by temperaturechange.temperature-compensating component A circuitcomponent, such as a capacitor or resistor, whosetemperature coefficient is equal in magnitude andopposite in sign to that of a conventional componentto which it is connected to cancel temperature-inducedvariation in the latter’s value.Tank capacitorTuningcontrolTemperaturecompensatingcapacitortemperature-compensating componenttemperature compensation The use of a device,such as a temperature-compensating component,to correct a temperature-induced deviationin the value of a conventional component.temperature control 1. The adjustment of temperature.2. The automatic maintenance of temperatureat a desired level, as in atemperature-controlled oven. 3. A device for controllingtemperature, as defined in 1 or 2.temperature-controlled crystal oscillator Abbreviation,TCCO. A high-precision crystal oscillatorin which the crystal plate (and sometimes the circuitry,as well) is held at constant temperature.temperature degree See DEGREE, 2 and THER-MOMETER SCALE.temperature derating Deliberate reduction of operatingcurrent and/or voltage of a device to aspecific temperature to ensure proper operation.Also see DERATING, DERATING CURVE, andDERATING FACTOR.