Definitions of Technical Terms
"A" "B" "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M",
"N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z"

"T" to "Ter", "Tes" "Thermb" to "Top", "Tor" to "Transf",
"Trans" to "Tre", "Triac" to "Tub", "Tun" to "Tz"

Tachometer. A small ac or dc generator, sometimes referred to as a rate generator, that converts its shaft speed into an electrical output. The tachometer is frequently used in servo-systems to sense the velocity of a load. An instrument that measures the rate at which a shaft is turning [angular velocity].

Tactile Switch. [Tact switch] A switch that provides some form of tactile feedback to the operator that the switch has been actuated. Normally a tactile switch is physically small having a very limited mechanical movement, requiring the switch to provide some form of tactile feedback so the user knows that the switch has been actuated or moved. Refer to this listing for Companies making tactile switches. Tactile switches are used for a number of applications, one of the more common applications are for membrane keypads.

Tandem. Pertaining to an arrangement or sequencing of networks, circuits, or links, in which the output terminals of one network, circuit, or link are connected directly to the input terminals of another network, circuit, or link.

Tank Circuit. A tuned circuit used to temporarily store energy. Also referred to as a parallel-resonant circuit, or LC circuit [Inductor Capacitor]. The components are placed in parallel in a Tank circuit. Also refer to Frequency Doubler using a tank circuit.

Tantalum Capacitor. A capacitor that uses tantalum as a dielectric. Read more from the Dictionary of Capacitor Terms

Tap. A fixed electrical connection point, normally at a location other than the two ends of a line. To draw energy from a circuit.

Tape and Reel. A method of packaging of electronic components in which a component is stored in a cavity of a plastic sheet and held in place by a tape covering the cavity. The plastic sheet and component covered by tape is than wound onto a reel which is than used by pick-and-place equipment. The reel holds some number of components, depending on the size of the component. In some cases a portion of the reel is sold or delivered and known as Cut-tape. Refer below for a picture of a section of a cut-tape reel.

Tape Drive. A unit for reading or writing to a magnetic tape. Also see Companies producing Tape Drives.

Taper. How the resistance of a potentiometer or variable resistor varies as the adjustment is changed. Read more about resistor terms and the Definition of Taper.

Tapped Delay Line. A delay line with multiple tapped outputs so the amount of delay may be selected by choosing another tap or point on the delay line. To change the delay on this type of circuit the output needs to be taken from a different output pin. Related terms, Delay Line, Programmable Delay Line. A tapped delay line may be passive, containing only an inductor [sometimes with a capacitor], or active using logic circuits to buffer or drive the signals. The total delay is the sum of all the individual tapped delays.

Tapped Resistor. A wire-wound, fixed resistor having one or more additional terminals along its length, generally for voltage-divider applications. Potentiometer Manufacturers.

Tapped Winding. A transformers with one or more additional terminals connected to the winding at places other than the extreme ends.

T-carrier. The generic designator for any of several digitally multiplexed telecommunications carrier systems. More detail on the T-carrier hierarchy.

T-coupler. A passive optical coupler having three ports (three fibers). Also called a Splitter.

Tee Connector. A style of connector shaped like a 'T'. The connectors may be any gender in any combination. A BNC style Tee is shown to the right, but a Tee connector could be almost any style. More Tee Connector Graphics [BNC, TNC]. Manufacturers of Coax Connectors

Tee Connector
BNC T Connector

Telecommunications. The transmission, emission, or reception of signs, signals, writings, images, or sounds. This is done by visual, oral, wire, radio, or other means. The term Telecommunications may also be abbreviated as Telcom.

Telemetry. An electrical system for measuring a quantity, transmitting the result and than indicating the quantity measured.

Temperature Coefficient. The ratio of the change in a parameter to the change in temperature. The amount of change of resistance in a material per unit change in temperature.

Temperature Compensation. The process of compensating for or nullifying the effects of temperature change on a circuit or device.

Temperature Cycling. Component or system testing which includes changing the ambient temperature during the test to exaggerate any faults that may exist. The largest temperature extremes range from -65 to +150 degrees C and may be used with the component powered or un-powered, depending on the test. Temperature cycling is also a form of accelerated test, reducing the testing time by stressing the component. Temperature testing normally also includes some amount of idle time at each increment in temperature.

Temperature Inversion. The condition in which warm air is formed above a layer of cool air that is near the earth's surface.

Temperature, Military. -55 to 125 degrees Celsius. The operational temperature range components or equipment is designed for to meet full military operation. [Military Temperature Range]

Temperature Sensor. A component or device that senses temperature changes and produces a change in its characteristics. A thermometer. See the Thermistor definition.

Temperature Shock. A rapid change in temperature.

Temperature Stabilizer. A circuit, component, or element used to keep the temperature of another device constant. Normally a temperature stabilizer is a heater used to keep a component from becoming to cold when the ambient temperature falls. A resistor or resistive element [contained within a component] could be considered a temperature stabilizer, as current is passed through the resistor. Also see heater. Many different symbols may be used to represent a temperature stabilizer, including just the symbol for a resistor, or a simple [H] in a block diagram.

Tempest. A term normally used to describe compromising emanations. These emanations are unintentionally radiated signals that could disclose classified information.

Tented Via. A via with dry film solder mask which completely covers both the via pad and its plated-through hole [PTH]. In the example to the right, the via pad and PTH is yellow while the solder mask is off-set in color. Also refer to the definition of Via.
The Lexicon of PWB Terms covers terms relating to circuit cards.

Tensile Strength. The greatest stress a substance can withstand along its length without tearing apart.

Terminal. An electrical connection. That part of the component package used in making an electrical, mechanical, or thermal connection. Examples of terminals are flexible leads, rigid leads, studs, and cases which serve as electrical connections. A number of board mounting terminals are shown in the graphic below. The graphic includes a wire warp terminal, a press-fit, a solder post, a solder cup [which holds solder], and a compression fit connection [as examples].

Different types of Board-Mount Terminals
Board Mount Terminals

Terminal Block. An insulating base utilizing one or more terminal connectors. In most cases the Terminal block contains a number of mechanical screw locations so wires may be electrically connected together via the screw connection. Well designed systems use round terminals which the wires are connected to. Other common terms include Terminal Strip, or Terminal Board, or screw terminal.

Terminal Board. Also called a terminal strip. An insulating base or slab equipped with terminals for connecting wiring.

Terminal Diagram. A diagram of a switch, relay, terminal board, or other component showing the connections to the equipment.

Terminal Impedance. The impedance as measured at the unloaded output terminals of transmission equipment or a line that is otherwise in normal operating condition.

Terminal Lug. A device attached to a conductor to permit connection to a terminal. [Terminal Lug Definition]

Terminal Stud. A terminal, generally post-like, having an axial portion of its body designed for projecting through or into a panel for mounting.

Termination. The load connected to a transmission line, circuit, or device. Also refer to the section on Mis-terminating a Transmission Line. An impedance, often resistive, that is connected to a transmission line or piece of equipment as a dummy load, for test purposes.

Ternary Signal. A signal that can assume, at any given instant, one of three significant conditions, such as power level, phase position, pulse duration, or frequency.

Tertiary Winding. A Tertiary winding is a third winding on a transformer, in many cases having the same turns ratio as the second winding. An additional secondary winding on a transformer. An example Transistor Blocking Oscillator using a Tertiary Winding. The word Tertiary means third.

PC motherboard

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