alternating current- Electric current that repeatedly reverses direction, twice each cycle. Usually at 60 cycles per second, or hertz, or 50 hertz elsewhere.
ampere - SI unit of electric current. A flow of one coulomb of change per second is one ampere.
diode- An 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- the rate at which electrical energy is converted into another form, such a s light, heat,or mechanical energy.
electric resistance- the resistance of a material to the flow of electric current through it; measured in ohms.
ohm- the SI unit of electric resistance. One ohm is the resistance of a device that draws a current of one ampere when a voltage of one volt is impressed across it.
Ohm's Law- The statement that the current in a circuit is directly proportional to the voltage impressed across it.
potential difference- The difference in electric potential between two points, free charge flows when there is a difference, and will continue until both points reach a common potential.
voltage source- A device, such as a dry cell or generator, that provides a potential difference.
