How does alternating current (AC) differ from direct current (DC)?

Alternating current (AC) is characterized by its ability to change direction periodically, which is a fundamental aspect of its operation. AC voltage oscillates over time, typically following a sine wave pattern, leading to cycles of positive and negative voltage. This periodic reversal means that the current flow alternates back and forth, which is in contrast to direct current (DC), where the flow of electrons moves in a single, constant direction.

This fundamental difference in behavior affects how AC and DC are utilized in various applications. For example, AC is commonly used in residential homes for powering appliances and lighting because it can be easily transformed to different voltage levels, making it suitable for long-distance transmission. On the other hand, DC is often employed in electronic devices and batteries where stable voltage and current are required, but it does not exhibit the periodic reversal of direction seen in AC.

Understanding this distinction between AC and DC is crucial for anyone studying electrical systems, particularly in the HVAC field, where alternating current is predominantly used for motors, compressors, and other electrical components.