Physics12 Electromagnetic Induction: Alternating Voltage and Current

Transformer is a device that increases or decreases the voltage associated with an alternating current. Alternating current is electric current that regularly reverses its direction. Transformers provide a simple, inexpensive way to change such voltage. They enable electric power companies to transmit alternating current easily and efficiently. Transformers also ensure the proper voltage for the circuits of home appliances, lights, industrial machinery, and other electric equipment.

Electric circuit is the closed path or paths followed by an electric current. An electric current is a flow of tiny particles called electrons. When current flows in a circuit, electric energy associated with the current can do useful work.

Alternating current (AC) is electric current that regularly reverses its direction of flow. Produced by AC generators, AC is used in most homes and businesses (see Electric generator). By contrast, direct current (DC) does not alternate. It always flows in the same direction and is produced by batteries and DC generators.