What distinguishes AC current from DC current?

The distinction between AC (Alternating Current) and DC (Direct Current) is fundamentally based on the flow direction of the electrical charge. In the case of DC, the electric charge flows consistently in one direction. This characteristic means that the voltage level remains constant over time. This unidirectional flow is utilized in batteries and power supplies where a steady voltage is necessary for devices.

On the other hand, AC is characterized by the fact that it periodically reverses direction. This means that the voltage and current alternate in cycles, leading to a waveform such as a sine wave. Most of the electrical power in homes and businesses is distributed as AC because it is more efficient for transmission over long distances and can easily be transformed to different voltage levels using transformers.

While options related to heat production and voltage levels involve other factors, they do not define the core characteristic that differentiates AC from DC. Thus, the key distinction lies in the directional flow of the current, making the understanding of DC's steady, one-way flow and AC's alternating nature crucial for grasping the fundamentals of electrical current types.