Alternating current: Electric current that repeatedly reverses direction, twice each cycle.
Ampere: SI unit of electric current.
Diode: Electronic device that restricts current to flow in a single direction in an electric circuit.
Direct current: Electric current whose flow of charge is always in one direction.
Electric current: The flow of electric charge; measured in amperes.
Electric power: Rate at which electrical energy is converted into another form, such as light, heat or mechanical energy.
Electric resistance: The resistance of a material to the flow of electric current through it.
Ohm: The SI unit of electric resistance.
Ohm's law: statement that the current in a circuit is directly proportional to the voltage impressed across the circuit.
Potential difference: difference in electric potential (voltage) between two points.
Voltage source: a device, such as a dry cell or generator, that provides a potential difference.