Direct Current (DC) is an electric current that flows in one direction, from the positive terminal to the negative terminal of a source like a battery. It has a constant voltage and doesn't change direction.
Alternating Current (AC) is an electric current that periodically changes direction, typically many times per second. It is generated by power plants and used in most electrical appliances in our homes and businesses. AC voltage changes from positive to negative in a cyclical manner, creating a waveform.
