To adjust the
correct value of
a reading by
comparison to a
standard.
capacitance
The ability of a
capacitor to
store an
electrical
charge. The
basic unit of
capacitance is
the Farad.
capacitive
reactance
The opposition
to current flow
provided by a
capacitor.
Capacitive
reactance is
measured in ohms
and varies
inversly with
frequency.
capacitor
An electronic
component having
capacitive
reactance.
capacitor
microphone
Microphone whose
operation
depends on
variations in
capacitance
caused by
varying air
pressure on the
movable plate of
a capacitor.
carbon-film
resistor
Device made by
depositing a
thin carbon film
on a ceramic
form.
carbon
microphone
Microphone whose
operation
depends on
pressure
variation in
carbon granules
causing a change
in resistance.
carbon
resistor
Resistor of
fixed value made
by mixing carbon
granules with a
binder which is
moulded and then
baked.
cascaded
amplifier
An amplifier
with two or more
stages arranged
in a series
configuration.
cascode
amplifier
A high frequency
amplifier made
up of a
common-source
amplifier with a
common-gate
amplifier in its
drain network.
cathode
The negative
terminal
electrode of a
device. The "N"
material in a
junction diode.
cathode
ray tube
(CRT) Vacuum
tube used to
display data in
a visual form.
Picture tube of
a television or
computer
terminal.
cell
Single unit used
to convert
chemical energy
into a DC
electrical
voltage.
center
frequency
Frequency to
which an
amplifier is
tuned. The
frequency half
way between the
cut-off
frequencies of a
tuned circuit.
center
tap
Midway
connection
between the two
ends of a
winding.
center
tapped rectifier
Circuit that
make use of a
center tapped
transformer and
two diodes to
provide full
wave
rectification.
center
tapped
transformer
A transformer
with a
connection at
the electrical
center of a
winding.
ceramic
capacitor
Capacitor in
which the
dialectric is
ceramic.
charge
Quantity of
electrical
energy.
charge
current
Current that
flows to charge
a capacitor or
battery when
voltage is
applied.
chassis
Metal box or
frame into which
components are
mounted.
chassis
ground
Connection to a
chassis.
chebyshev
filter
A type of active
filter
characterized by
high roll-off
rates (40 dB per
decade per pole)
and midband gain
that is not
constant.
choke
Inductor used to
oppose the flow
of alternating
current.
circuit
Interconnection
of components to
provide an
electrical path
between two or
more components.
circuit
breaker
A protective
device used to
open a circuit
when current
exceeds a
maximum value.
In effect a
reusable fuse.
clamper
A diode circuit
used to change
the DC level of
a waveform
without
distorting the
waveform.
clapp
oscillator
A variation of
the Colpitts
oscillator. An
added capacitor
is used to
eliminate the
effects of stray
capacitance on
the operation of
the basic
Colpitts
oscillator.
class A
amplifier
A linear
amplifier biased
so the active
device conducts
through 360
degrees of the
input waveform.
class B
amplifier
An amplifier
with two active
devices. The
active
components are
biased so that
each conducts
for
approximately
180 degrees of
the input
waveform cycle.
class C
amplifier
An amplifier in
which the active
device conducts
for less than
180 degrees of
the input
waveform cycle.
clipper
A diode circuit
used to
eliminate part
of a waveform
clipping
Distortion
caused by
overdriving an
amplifier.
clock
A square
waveform used
for
synchronizing
and timing of
several
circuits.
closed
circuit
Circuit having a
complete path
for current
flow.
closed-loop gain
Gain of an
amplifier when a
feedback path is
present.
coaxial
cable
Transmission
line in which
the signal
carrying
conductor is
covered by a
dialectric and
another
conductor.
coefficient of
coupling
The degree of
coupling between
two circuits.
coercive
force
(H) Magnetizing
force needed to
reduce residual
magnetism in a
material to
zero.
collector
The
semiconductor
region in a
bipolar junction
transistor
through which a
flow of charge
carriers leaves
the base region.
collector
characteristic
curve
A graph of
collector
voltage over
collector
current for a
given base
current.
color
code
Set of colors
used to indicate
value of a
component.
colpitts
oscillator
An oscillator
with a pair of
tapped
capacitors in
the feedback
network.
common-anode
display
A multisegment
light emitting
diode (LED) with
a single
positive voltage
input
connection.
Separate cathode
connections are
provided for
each individual
segment.
common
cathode display
A multisegment
light emitting
diode (LED) with
a single
negative voltage
input
connection.
Separate anode
connections are
provided for
each individual
segment.
common
base amplifier
A BJT circuit in
which the base
connection is
common to both
input and
output.
common
collector
amplifier
A BJT circuit in
which the
collector
connection is
common to both
input and
output.
common
drain amplifier
A FET circuit in
which the drain
connection is
common to both
input and
output.
common
emitter
amplifier
A BJT circuit in
which the
emitter
connection is
common to both
input and
output.
common
gate amplifier
A FET circuit in
which the gate
connection is
common to both
input and
output.
common
source amplifier
A FET circuit in
which the source
connection is
common to both
input and
output.
common-mode
rejection ratio
(CMRR) The ratio
of op-amp
differential
gain to
common-mode
gain. A measure
of an op-amp's
ability to
reject
common-mode
signals such as
noise.
common-mode
signals
Signals that
appear
simultaneously
at two inputs of
an operational
amplifier
(op-amp). Common
mode signals are
always equal in
amplitude and
phase.
comparitor
An op-amp
circuit that
compares two
inputs and
provides a DC
output
indicating the
polarity
relationship
between the
inputs.
complementary
symmetry
amplifier
A class B
amplifier using
matched
complementry
transistors.
Does not require
a phase inverter
for push-pull
output.
complementry
transistors
Two transistors,
one NPN and one
PNP having near
identical
charastics.
N-channel and
P-channel FETs
can also be
complementry.
complex
numbers
Numbers composed
of a real number
part and an
imaginary number
part.
compliance
The maximum
possible
peak-to-peak
output of an
amplifier.
constant
current circuit
Circuit used to
maintain
constant current
to a load having
resistance that
changes.
contact
Current carrying
part of a
switch, relay or
connector.
continuity
Occurs when a
complete path
for current
exists.
conventional
current flow
Concept of
current produced
by the movement
of positive
charges towards
the negative
terminal of a
source.
copper
loss
Power lost in
transformers,
generators,
connecting wires
and other parts
of a circuit due
to current flow
through the
resistance of
copper
conductors.
core
Magnetic
material within
a coil used to
concentrate the
magnetic field.
coulomb
Unit of electric
charge. A
negative coulomb
charge consists
of 6.24 × 1018
electrons.
counter
electromotive
force
(counter emf)
Voltage induced
into an inductor
due to an
alternating or
pulsating
current. Counter
emf is always in
polarity
opposite to that
of the applied
voltage.
Opposing a
change of
current.
coupling
To
electronically
connect two
circuits so that
signal will pass
from one to the
other.
covalent
bond
The way some
atoms complete
their valence
shells by
sharing valence
electrons with
neighbouring
atoms.
crossover
distortion
Distortion
caused by both
devices in a
class B
amplifier being
cut-off at the
same time.
crowbar
Circuit used to
protect the
output of a
souce from a
short circuited
load. Load
current is
limited to a
value the source
can deliver
without damage.
CRT
Abbreviation for
cathode ray
tube.
crystal
Natural or
synthetic
piezoelectric or
semiconductor
material with
atoms arranged
with some degree
of geometric
regularity.
crystal-controlled
oscillator
Oscillator that
uses a quartz
crystal in its
feedback path to
maintain a
stable output
frequency.
current
Measured in
amperes, it is
the flow of
electrons
through a
conductor. Also
know as electron
flow.
current
amplifier
Amplifier to
increase signal
current.
current
divider
Parallel network
designed to
divide the total
current of a
circuit
current
feedback
Feedback
configuration
where a portion
of the output
current is fed
back to the
amplifier input.
current-limiting
resistor
Resistor in the
path of current
flow to control
the amount of
current drawn by
a device.
current
mirror
Term used to
describe the
fact that DC
current through
the base circuit
of a class B
amplifier is
approximately
equal to the DC
collector
current.
cutoff
Condition when
an active device
is biased such
that output
current is near
zero or beyond
zero.
cutoff
frequency
Frequency at
which the power
gain of an
amplifier falls
below 50% of
maximum.
cycle
When a repeating
wave rises from
zero to a
positive maximum
then back to
zero and on to a
negative maximum
and back to zero
it is said to
have completed
one cycle
