18WuD2x

304 FT-cut crystal • full-scale sensitivity
FT-cut crystal A piezoelectric plate cut from a
quartz crystal at an angle of +57°, with respect to
the z-axis. Also see CRYSTAL AXES and CRYS-
TAL CUTS.
ft-Lb Abbreviation of FOOT-LAMBERT.
ft-lb Abbreviation of FOOT-POUND.
Fuchs antenna A simple antenna consisting of a
single-wire radiator without feeder or transmission
line, connected directly to the transmitter. It
is usually an odd multiple of 0.25 wavelength
long. When a good radio-frequency (RF) ground is
used, this antenna can be effective at high frequencies,
although part of its radiated field is often
inside the transmitter building.
TX
Fuchs antenna
Radiating
element:
odd multiple
of λ/4
fuel alarm A sensing circuit that actuates an
alarm when the fuel in a tank or reservoir falls to
a prescribed level.
fuel cell A generator that produces electricity directly
from a reaction between fuel substances,
such as hydrogen and oxygen.
fuel-flow alarm An electronic circuit that actuates
an alarm when fuel flow changes from a prescribed
value.
fuel-flow control A servo system that automatically
maintains or corrects the flow rate of a fuel.
fuel-flow gauge See FUEL-FLOW METER.
fuel-flow indicator See FUEL-FLOW METER.
fuel-flow meter An instrument for measuring fuel
flow rate.
fuel-flow switch A switch that is actuated by fuel
flowing in pipes or other channels.
fuel gauge An instrument consisting of a transducer
that senses the level of liquid fuel in a tank
and delivers a proportional output current or
voltage, and an electric meter whose needle is deflected
in proportion to the current or voltage
and, therefore, to the fuel level. Alternatively, the
meter can be a direct-readout digital device,
showing the number of gallons remaining in the
tank, and/or the extent to which the tank is full
(fraction or percentage).
fuel meter See FUEL GAUGE.
fuel-pressure indicator An instrument for measuring
fuel pressure in pipes or other channels.
fuel-pressure meter See FUEL-PRESSURE INDI-
CATOR.
full adder In a digital computer, an adder circuit
that can handle the carry signal, as well as the binary
elements that are to be added. Also see
ADDER and CARRY. Compare HALF ADDER.
full bridge A bridge-rectifier circuit in which each
of the four arms contains a diode. By comparison,
the three-quarter bridge contains a resistor in
one arm; the half bridge, resistors in two arms;
and the quarter bridge, resistors in three arms.
full-duplex system In data communications, a
system that transmits data in both directions simultaneously
and continuously. Compare HALF-
DUPLEX SYSTEM.
full-focus yoke See COSINE YOKE.
fullhouse A multichannel radio-control model
plane system that allows the use of a realistic
complement of working control surfaces.
full-load current The output current from a
source when the load is maximum (that is, the
load resistance is minimum).
full-load power The power drawn from a source
when the load is maximum (that is, the load resistance
is minimum).
full-load voltage The output voltage of a source
when full power is drawn [i.e., when the load is
maximum (that is, the load resistance is minimum)].
full-load wattage See FULL-LOAD POWER.
full-power frequency response The highest frequency
at which a signal can fluctuate at full voltage
(peak-to-peak) without causing distortion of
more than a certain specified amount.
full-range speaker See MONORANGE SPEAKER.
full scale 1. The operating range of an instrument.
2. In an analog meter, the quantity indicated by
maximum deflection of the needle (usually at the
extreme right-hand end of the calibrated scale).
3. Transducer output as a function of highest allowable
input stimulus.
full-scale current Symbol, I FS . In a digital-toanalog
converter, the maximum current that can
occur at the output.
full-scale error For an electrical indicating instrument,
the rated full-scale input signal minus the
actual input signal that causes a full-scale deflection.
Thus, the predictable error in an instrument,
expressed as a percentage of the full-scale reading.
full-scale frequency Generally expressed in Hertz
(Hz) or kilohertz (kHz). The maximum frequency
at which a voltage-to-frequency converter can operate
while remaining within its specifications.
full-scale sensitivity The current, voltage, or
power required to deflect a meter mechanism to
full scale.