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THERMAL RUNAWAY—A conduction that exists when heat causes more electron-hole pairs to be
generated, which, in turn, causes more heat and which may eventually cause diode destruction [7].
THERMAL TRIP ELEMENT—A circuit breaker trip element that uses the increased bending of a
bimetallic strip caused by increased current to open a circuit [3].
THERMIONIC EMISSION—Emission of electrons from a solid body as a result of elevated temperature
[6].
THERMISTOR—(1) A semiconductor device whose resistance varies with temperature [4]. (2) A type of
bolometer characterized by a decrease in resistance as the dissipated power increases [16].
THERMOCOUPLE—A junction of two dissimilar metals that produces a voltage when heated [1].
THERMOCOUPLE METER MOVEMENT—A meter movement that uses the current induced in a
thermocouple by the heating of a resistive element to measure the current in a circuit; used to measure
ac or dc [3].
THERMOPLASTIC—A synthetic mixture of rosins that is flexible and used as an insulting material.
Generally used as an insulator for low- and medium-range voltages [4].
THETA—The Greek letter ( ) used to represent phase angle [2].
THICK FILM COMPONENTS—Passive circuit components (resistors and capacitors) having a thickness
of 0.001 centimeter [14].
THIN FILM COMPONENTS—Passive circuit elements (resistors and capacitors) deposited on a substrate
to a thickness of 0.0001 centimeter [14].
THREE-ELEMENT ARRAY—An array with two parasitic elements (reflector and director) and a driven
element [10].
THREE-DIMENSIONAL RADAR (3D)—A radar set that measures the range, bearing and altitudes of a
target [18].
THROW—In a switch, the number of different circuits each pole can control; for example, single throw and
double throw [3].
THYRATRON—A gas tube used as a modulator switching device [18].
THYRATRON TUBE—A gas-filled triode in which a sufficiently large positive pulse applied to the
control grid ionizes the gas and causes the tube to conduct, after which the control grid has no effect in
conduction [6] [12].
TICKLER COIL—A small coil connected in series with the collector or plate circuit of a transistor or tube
and inductively coupled to the base or grid-circuit coil to establish feedback (regeneration) [9].
TIME CONSTANT—Time required for an exponential quantity to change by an amount equal to 63.2
percent of the total change that can occur [2] [9].
TIME-DIVISION MULTIPLEXING—The process that periodically samples the full 360 degrees of each
sine wave. The sample can be of a received signal or of a signal to be transmitted [17].
