What is the difference between AC and DC current?

The difference between AC (Alternating Current) and DC (Direct Current) is fundamental to understanding electrical systems. AC is characterized by the flow of electric charge that periodically reverses direction. This means that the current switches back and forth, creating a waveform that typically follows a sinusoidal pattern. This alternating nature allows AC to be distributed over long distances with less energy loss, making it the primary form of electricity used in homes and businesses.

On the other hand, DC flows continuously in one direction. It maintains a constant polarity, which means that the electric charge moves steadily from the negative side to the positive side without reversing. This characteristic is why batteries, which provide a stable voltage output, are classified as DC sources.

The statement regarding DC being higher in voltage than AC is not universally accurate, as voltage levels for both AC and DC can vary widely based on their intended application and system design. Therefore, focusing on the fundamental definitions, AC's periodic reversal of direction contrasts with DC's unidirectional flow, making the selected answer the most accurate representation of their differences.