Time it takes the falling edge
of a pulse to go from 90% of
peak voltage to 10% of peak
voltage.
farad
The basic unit of capacitance.
feedback
A portion of the output signal
of an amplifier which is
connected back to the input of
the same amplifier.
feedback amplifier
An amplifier with an external
signal path from its output back
to its input.
ferrite
A powdered, compressed and
sintered magnetic material
having high resistively. The
high resistance makes eddy
current losses low at high
frequencies.
ferrite bead
Ferrite composition in the form
of a bead. Running a wire
through the bead increases the
inductance of the wire.
ferrite-core inductor
An inductor wound on a ferrite
core.
ferrites
Compound composed of iron oxide,
a metallic oxide and ceramic.
The metal oxides include zinc,
nickel, cobalt or iron.
ferrous
Composed of and or containing
iron. A ferrous metal exhibits
magnetic characteristics as
opposed to non-ferrous material.
fiber optics
Laser's light output carries
information that is conveyed
between two points by thin glass
optical fibers.
field effect transistor
(FET) A voltage controlled
transistor in which the source
to drain conduction is
controlled by gate to source
voltage.
filament
Thin thread of carbon or
tungsten which produces heat or
light with the passage of
current.
filter
Network consisting of
capacitors, resistors and/or
inductors used to pass certain
frequencies and block others.
flip flop
A bistable multivibrator. A
circuit which has two output
states and is switched from one
to the other by means of an
external signal (trigger).
floating ground
Common connection in a circuit
that provides a return path for
current but is not connected to
an earth ground.
flow soldering
Flow or wave soldering technique
in large scale electronic
assembly to solder all the
connections on a printed circuit
board by moving the board over a
wave of molten solder.
flux
Material used to remove oxide
films from the surface of metals
in preparation for soldering.
flux
In magnetism, the magnetic field
consisting of lines of force.
flux density
The concentration of magnetic
lines of force. Determines
strength of the magnetic field.
flywheel effect
Sustaining effect of oscillation
in an LC circuit.
forward bias
A PN junction bias which allows
current to flow through the
junction. Forward bias decreases
the resistance of the depletion
layer.
free electrons
Electrons that are not in any
orbit around a nucleus.
free running
multivibrator
A multivibrator that produces a
continuous output waveform
without any signal input. A
square wave generator used to
produce a clock signal.
frequency
Rate of recurrence of a periodic
wave. Measured in Hertz (cycles
per second).
frequency-division
multiplex
(FDM) Transmission of two or
more signals over a common path
by using a different frequency
band for each signal.
frequency-domain analysis
A method of representing a
waveform by plotting its
amplitude against frequency.
frequency meter
Meter used to measure frequency
of periodic waves.
frequency multiplier
A harmonic conversion circuit in
which the frequency of the
output signal is an exact
multiple of the input frequency.
frequency response
Indication of how well a circuit
responds to different
frequencies applied to it.
frequency response curve
A graph of amplitude over
frequency indicating a circuit
response to different
frequencies.
full scale deflection
(FDS) Deflection of a meter's
pointer to the farthest position
on the scale.
full wave rectifier
Rectifier that makes use of the
full AC wave in both the
positive and negative half
cycles.
function generator
Signal generator that can
produce sine, square, triangle
and sawtooth output waveforms.
fundamental frequency
Lowest frequency in a complex
waveform.
fuse
A protective device in the
current path that melts or
breaks when current exceeds a
predetermined maximum value
