What is alternating current (AC)?

Alternating current (AC) is characterized by its ability to reverse direction periodically. This means that the flow of electric charge continuously changes direction, alternating back and forth at regular intervals. This cyclical behavior is typically measured in Hertz (Hz), indicating the number of cycles per second. The ability of AC to change direction allows it to be transmitted efficiently over long distances, making it the predominant form of electrical power used in homes and businesses.

Understanding AC is crucial because it contrasts with direct current (DC), where the flow of electric charge is unidirectional and constant. Moreover, the other descriptions of electric current fail to capture the essential feature of AC's periodic reversal, making this explanation particularly relevant for grasping the concept in electrical engineering and practical applications.