Thomson is best known as a physicist who
championed the absolute temperature system
that now bears his name (Kelvin). Thom-
son did significant work to expand Fara-
day’s ideas.
It was Thomson’s work that
Maxwell would extend into his seminal pub-
lications on electromagnetics. Thomson re-
ceived a knighthood for his theoretical sug-
gestions for the use of low-voltage signals in
the trans-Atlantic telegraph cable. Thomson
was proved correct when on a third attempt, a
cable was laid and worked. An earlier high-
voltage cable had failed.
thoriated
pertains to a metal to which the
element thorium has been added.
thrashing
in a paging system, the effect
of excessive and continual page transfers that
can occur because the memory is overcom-
mitted and programs cannot obtain sufficient
main memory.
thread
in software processes, a thread of
control is a section of code executed inde-
pendently of other threads of control within
a certain program.
three-antenna gain measurement method
technique based on Friis transmission for-
mula in which the gain of each of three dif-
ferent antennas is calculated from a measure-
ment of three insertion loss values (corre-
sponding to all three combinations of antenna
pairs) and the calculated propagation loss be-
tween the antenna pairs.
three-gun color display
a color-TV pic-
ture tube having a separate gun for each pri-
mary color (red, green, and blue).
three-lamp synchronizing
a method used
to connect a three-phase power system in par-
allel to another one. In order to connect two
systems, they must have the same voltage
magnitude, frequency, and phase-shift. To
determine that is the case, an open switch is
connected between the phases of the two sys-
tems and a lamp is connected across the open
switch pole in each phase. If the criteria pre-
viously listed are met, the lamps will all be
dark. If there is a difference in voltage, the
lamps will glow. If there is a difference in fre-
quency, the lamps will alternately glow and
go dark in unison. Finally, if the two sides
have different phase rotations, the lamps will
blink sequentially as only one phase can be
aligned at a time. In order to synchronize
the two systems, it is necessary to close the
contactor when the phase-shift is minimum,
which means that the three lights are dark.
three-level laser
laser in which the most
important transitions involve only three en-
ergy states; usually refers to a laser in which
the lower level of the laser transition is sep-
arated from the ground state by much less
than the thermal energy
kT . Contrast with
four-level laser
.
three phase fault
a fault on a three phase
power line in which all three conductors have
become connected to each other and possibly
the ground as well.
Three-Mile Island
typically refers to a
cooling failure at a nuclear power plant on the
Susquehanna River in central Pennsylvania,
USA in 1979.
three-phase inverter
an inverter with a
three-phase AC voltage output.
Three-phase inverter.
three-phase rectifier
a rectifier with a
three-phase AC voltage input.
three-point starter
a manual DC motor
starter in which a handle is pulled to start
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2000 by CRC Press LLC