What is the difference between AC and DC current?

The distinction between AC (Alternating Current) and DC (Direct Current) fundamentally lies in their flow characteristics. AC changes direction periodically, meaning that the flow of electric charge reverses direction at regular intervals. This is typical for the electricity supplied to homes and businesses, allowing it to travel long distances efficiently. The frequency of this directional change is measured in hertz (Hz), with common standards being 50 or 60 Hz, depending on the region.

In contrast, DC flows in a single direction, delivering a constant voltage. This type of current is commonly found in batteries and electronic devices, where stable and unidirectional power is essential for operations.

Understanding this difference is crucial in electrical installation and maintenance because it informs how devices operate and how systems are designed. For instance, appliances are often designed to work with either AC or DC power, and installing them incorrectly can cause malfunctions or hazards. The other options misrepresent these fundamental characteristics of current types, highlighting why clarity in the distinction is important for both safety and functionality.