A direct current has a fixed value that is independent of time. An alternating current, on the other hand, has a value that changes with time. This change in current follows a pattern that we can char...A direct current has a fixed value that is independent of time. An alternating current, on the other hand, has a value that changes with time. This change in current follows a pattern that we can characterize by it period—the time for one complete cycle—or by its frequency, which is the reciprocal of its period. Frequency is reported in hertz (Hz), which is equivalent to one cycle per second.
