Alternating Current- Electric current that repeatedly reverse direction, twice each cycle. Usually at 60 cycles per second, or hertz(HZ), in North America, or 50 hertz else where.
Ampere- SI unite of electric current. A flow of one coulomb of charge per second is ampere (symbole A)
Diode- An electronic device that restricts current to flow in single direction in an electric circuit.
Direct current- Electric current whose flow of change is always in one direction.
Electric current-The flow of electric charge; measured in amperes.
Electric power- The rate at which electrical energy is coverted in to another form, such as light, heat, or mechanical energy (or converted frm another form into electrical 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 resista ce 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 resistance of the circuit.
Potentioal difference- The difference in electirc potential (voltage) between tw points. Free charge flows when there is a differece, and will conitnjue until both points reach a common potential.