18WuD2x

thy • time-interval mode 685
thy Abbreviation of THYRATRON.
thyratron A gas triode or gas tetrode used principally
for switching and control purposes. Thyratron
action differs from that of the vacuum tube
in the unique behavior of the thyratron control
electrode (grid): Anode current starts to flow
abruptly when grid voltage reaches a particular
value, at which point the grid provides no further
control; anode current continues to flow until the
anode voltage is either interrupted or reversed.
thyratron inverter An inverter circuit (see IN-
VERTER, 1) using thyratrons as the switching
devices. Also see THYRATRON.
Thyrector A silicon diode exhibiting very high resistance
(approaching that of an insulator) up to
a certain voltage, beyond which the unit switches
to a low-resistance conducting state.
thyristor 1. A pnpn-type bistable semiconductor
device having anode, cathode, and gate terminals
that is used as an electronic switch. 2. The
generic term for all thyratronlike solid-state devices,
such as the silicon-controlled rectifier.
Thyrite Ceramic silicon carbide, a nonlinear resistance
material, or a resistor made of this material.
The resistance of Thyrite decreases sharply
as the applied voltage is increased. Thyrite resistors
are used in voltage regulators, equipment
protectors, lightning arresters, curve changers,
and similar devices.
THz Abbreviation of TERAHERTZ.
Ti Symbol for TITANIUM.
tickler A (usually small) coil, through which energy
is inductively fed back from the output to the
input of a circuit to induce oscillation.
tickler coil See TICKLER.
tickler-coil regeneration Positive feedback obtained
via inductive coupling between a small coil
(tickler) in the output circuit of an amplifier, and
a (usually larger) coil in the input circuit. Also see
TICKLER.
+12 V
In
Out
Tickler
tickler-coil regeneration
tickler oscillator An oscillator circuit in which
positive feedback is obtained through inductive
coupling between an output (tickler) coil and an
input coil.
tie A bracket, clamp, clip, ring, or strip for holding
several wires tightly as a cable or bundle.
tie cable 1. A cable that connects two distributing
points in a telephone system. 2. Any cable that
interconnects two circuits.
tie point A lug, screw, or other terminal to which
wires are connected at a junction.
tie-point strip A terminal strip with lugs to which
conductors can be soldered.
tight coupling See CLOSE COUPLING.
tilt switch A device, such as a mercury switch,
that is actuated by tilting it to a certain angle.
timbre The quality that distinguishes the sound of
one voice or instrument from that of another,
largely because of harmonic content.
time Symbol, t. 1. The instant at which an event
occurs. 2. The instant at which a time-base variable
reaches a given value. 3. The interval between
two instants, commonly called duration or
length of time. Also see STANDARD TIME, TIME
BASE, TIME ZONE, and ZERO TIME.
time base Time as the independent variable in a
physical relation or function. It appears in expressions
such as pulses per second, feet per
minute, watts per hour, etc.
time compressor In audio recording and reproduction,
a device that speeds up or slows down
the tempo without changing the audio frequencies.
It is used for special effects.
time constant See ELECTRICAL TIME CONSTANT
and MECHANICAL TIME CONSTANT.
time delay See DELAY, 1, 2.
time-delay relay See DELAY RELAY.
time-delay spectrometry In acoustics, a method
of simulating an echo-free environment within an
enclosure that is actually not echo-free.
time-division multiplexing Abbreviation, TDM. In
data and computer communications, a timesharing
technique in which several terminals use
the same channel by transmitting data at regular,
staggered intervals (i.e., one is active while the
others are idle). This gives the appearance of simultaneous
real-time operation.
time-division-multiplex switch A switch with multiple
ports—each port corresponding to a certain
time slot in a time-division-multiplex scheme. The
input and output (send and receive) ports are connected
by selecting the same TIME SLOT for each.
time-domain reflectometry Abbreviation, TDR.
Measuring the reflective characteristics of a device
or system by superimposing the direct and
reflected components of a step-formed test signal
on a time-calibrated oscilloscope screen.
time duration See TIME, 3.
time-duration modulation See PULSE-DURA-
TION MODULATION.
time factor The ratio ta/tr, where ta is analog time
(the relativistic duration of an event as simulated
by a computer), and tr is real time (the actual duration
of the event). Also called TIME SCALE.
time-interval mode In computer operations, operation
that allows a number of events to be
counted between two points on a waveform.