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.
|