18WuD2x

FET current meter • field coil 281
FET current meter An ammeter, milliammeter, or
microammeter having a self-contained amplifier
that uses field-effect transistors. Also see ELEC-
TRONIC CURRENT METER.
FET op-amp 1. An operational amplifier composed
of field-effect transistors and associated components.
2. An operational amplifier having a fieldeffect
transistor in its input stage.
FET voltmeter A voltmeter using a field-effect
transistor amplifier for high-impedance input.
Also see ELECTRONIC VOLTMETER.
fiberoptics 1. Also called optical fibers. Extruded
materials, such as certain plastic filaments, that
provide paths for light. 2. The science of developing
and using communications systems that use
optical fibers to transfer data.
Fiber
Reflection
point
Reflection
point
Light
beam
fiberoptics
FET VOM A volt-ohm-milliammeter (VOM) using a
field-effect transistor amplifier for increased sensitivity
and high input impedance.
FF Abbreviation of FLIP-FLOP.
fF Abbreviation of FEMTOFARAD.
FFI Abbreviation of FUEL-FLOW INDICATOR.
fhp Abbreviation of FRACTIONAL HORSEPOWER.
fiber 1. A tough, vulcanized insulating material.
Dielectric constant, 2.5 to 5. Dielectric strength,
2 kV/mm. 2. A thin thread of a material. 3. Also
called optical fiber. A light-conductive transparent
filament; see FIBEROPTICS, 1.
fiber electrometer An instrument for measuring
small quantities of electricity. It consists of a
thin thread, such as one of plasticized quartz,
hanging freely between two knife-edged metal
pieces that are charged by the electricity being
measured. The charge draws the fiber away from
its position of rest. The movement can be observed
with a microscope. A special form of this
instrument, using two fibers, is the bifilar electrometer.
fiber needle A soft phonograph needle made from
a fiber. It produces less disk wear than other
styli, but is short-lived.
fiber metallurgy A process in which metallic fibers
or filaments are grown.
fiberoptic bundle A cable of optical fibers. See
FIBEROPTICS, 1.
fiberoptic coupling Also called optical coupling. A
method of coupling in which a light-conducting
fiber is placed between a light (signal) source and
a photoreceptor. Also see FIBEROPTICS, 1, 2.
fiberoptic scrambler A fiberscope in which a center
section of fibers in the core is deliberately disoriented
before the bundle is encapsulated; when
cut, one half can decode the image encoded by
the other half. See FIBERSCOPE.
fiberscope A flexible bundle of optical fibers having
a lens at each end; it is used to view areas that
are otherwise inaccessible to view.
fiber stylus See FIBER NEEDLE.
fibre Alternate (Brit.) spelling of FIBER.
fibrillation Dangerous, irregular beating of the
heart that often follows electric shock. Also see
CARDIAC STIMULATOR and DEFIBRILLATION.
fidelity The degree to which a circuit or device
transmits a signal without distorting it. Pertains
especially to acoustic devices and stereo audio
equipment.
field 1. A volume of space in which a force is operative.
See, for example, ELECTRIC FIELD and
MAGNETIC FIELD. 2. Half of a video image, consisting
either of all the even-numbered lines, or
all the odd-numbered lines. 3. A computer record
subdivision containing an information unit (e.g.,
a bank account record might have deposits as a
field).
field circuit breaker A circuit breaker designed to
control the field excitation of a motor or other device.
field coil 1. The winding on the field pole of a motor
or generator. 2. The winding on the pole of an
electrodynamic speaker. 3. The main coil of a relay.
4. The fixed coil in an electrodynamometer.