What is the term for electrical current that periodically reverses direction?

Alternating current, commonly referred to as AC, is characterized by the periodic reversal of its direction. In this type of current, the flow of electrons alternates back and forth, typically in a sine wave pattern. This means that at one moment, the current flows in one direction, and after a certain period, it reverses and flows in the opposite direction. This cyclical nature of alternation is essential for various applications, especially in power distribution, as it allows for efficient transmission over long distances and is capable of powering a wide variety of household and industrial devices.

In contrast, direct current (DC) maintains a constant direction and does not reverse, which makes it suitable for applications like batteries and electronic devices that require a steady voltage. Static current is not a recognized term in electrical engineering, as it typically refers to electricity at rest rather than in motion. Polyphase current involves multiple alternating currents that are out of phase with each other, but it too does not encapsulate the concept of single-phase electrical current reversing direction. Therefore, the definition of alternating current aligns directly with the concept of periodic direction reversal in electrical flow, making it the correct choice.