- A
- Abbreviation for "ampere" a unit of
electrical current.
- absorption
- Loss or dissipation of energy as it
travels through a medium, Example: radio
waves lose some of their energy as they
travel through the atmosphere.
- AC
- Abbreviation for "Alternating
Current"
- acceptor atoms
- Trivalent atoms that accept free
electrons from pentavalent atoms.
- AC coupling
- Circuit that passes an AC signal
while blocking a DC voltage.
- AC/DC
- Equipment that will operate on
either an AC or DC power source.
- AC generator
- Device used to transform mechanical
energy into AC electrical power.
- AC load line
- A graph representing all possible
combinations of AC output voltage and
current for an amplifier.
- AC power supply
- Power supply that delivers an AC
voltage.
- active component
- A component that changes the
amplitude of a signal between input and
output.
- active filter
- A filter that uses an amplifier in
addition to reactive components to pass
or reject selected frequencies.
- active region
- The region of BJT operation between
saturation and cutoff used for linear
amplification.
- AC voltage
- A voltage in which the polarity
alternates.
- ADC
- Abbreviation for "analog to digital
converter"
- Admittance
- (symbol "Y") Measure of how easily
AC will flow through a circuit.
Admittance is the reciprocal of
impedance and is measured in siemens.
- AF
- Abbreviation for "audio frequency".
- AFC
- Abbreviation for "automatic
frequency control".
- AGC
- Abbreviation for "automatic gain
control"
- alkaline cell
- A primary cell that delivers more
current than a carbon-zinc cell. Also
known as an "alkaline manganese cell".
- alligator clip
- Spring clip on the end of a test
lead used to make a temporary
connection.
- alpha
- Ratio of collector current to
emitter current in a bipolar junction
transistor (BJT). Greek letter alpha "a"
is the symbol used.
- alternating current
- An electric current that rises to a
maximum in one direction, falls back to
zero and then rises to a maximum in the
opposite direction and then repeats.
- alternator
- Name for an AC generator.
- AM
- Abbreviation for "amplitude
modulation"
- ammeter
- A meter used to measure current.
- ampere
- Unit of electrical current.
- amplifier
- A circuit that increases the
voltage, current, or power of a signal.
- amplitude:
- Magnitude or size of a signal
voltage or current.
- analog
- Information represented as
continously varying voltage or current
rather than in discrete levels as
opposed to digital data varying between
two discrete levels.
- anode
- The positive electrode or terminal
of a device. The "P" material of a
diode.
- antenna, transmitting
- A device that converts an electrical
wave into an electromagnetic wave that
radiates away from the antenna.
- antenna, receiving
- A device that converts a radiated
electromagnetic wave into an electrical
wave.
- apparent power
- Power attained in an AC circuit as a
product of effective voltage and current
which reach their peak at different
times.
- arc
- Discharge of electricity through a
gas such as lightning discharging
through the atmosphere.
- armature:
- The rotating or moving component of
a magnetic circuit.
- armstrong oscillator
- An oscillator that uses an isolation
transformer to achieve positive feedback
from output to input.
- astable multivibrator
- An oscillator that produces a square
wave output from a DC voltage.
- atom
- The smallest particle that an
element can be broken down into and
still maintain its unique identity.
- atomic number
- The number of positive charges or
protons in the nucleus of an atom.
- attenuate
- To reduce the amplitude of an action
or signal. The opposite of
amplification.
- audio
- Relating to frequencies that can be
heard by the human ear. Approximately 20
Hz. to 20 kHz.
- autotransformer
- A single winding transformer where
the output is taken from taps on the
winding.
- average value
- A value of voltage or current where
the area of the wave above the value
equals the area of the wave below the
value.
- AVC
- Abbreviation for "automatic volume
control"
- avionics
- Aviation electronics.
- AWG
- Abbreviation for "american wire
gauge". A gauge that assigns a number
value to the diameter of a wire.
