Alternating current (AC) is a type of electrical current that periodically reverses direction. Unlike direct current (DC), which flows in a single direction, AC changes its flow back and forth, typically in a sinusoidal waveform. This characteristic makes AC suitable for powering homes and businesses, as it can be easily transformed to different voltages. AC is generated by devices like alternators and is commonly used in electrical grids. The frequency of AC, measured in hertz (Hz), indicates how many times the current changes direction per second. In many countries, the standard frequency is 50 or 60 Hz, allowing for efficient transmission of electricity over long distances.