Alternating Current and AC Terminology

Unlike direct current (DC), alternating current does not maintain one constant direction. A periodic AC waveform repeats after a fixed interval called its time period `T`. The number of complete cycles produced per second is called frequency `f`: f = 1T and: T = 1f The SI unit of frequency is hertz (Hz). One hertz means one complete cycle per second. Important AC terms include: Cycle: One complete repetition of the waveform. Time period: Time required for one complete cycle. Frequency: Number of cycles per second. Peak value: Maximum magnitude reached by current or voltage. Instantaneous value: Value of current or voltage at a particular instant. AC: changes magnitude; periodically reverses direction. DC: * flows in one direction.

**f = 1T T = 1f**