What is Direct Current?

Direct Current (DC) is defined as the flow of electric charge in a constant direction. This uninterrupted flow is typically produced by power sources like batteries, which deliver a stable voltage and thus maintain a consistent current that does not reverse or change its direction.

Understanding that DC flows in only one direction is crucial for various applications, including electronics, telecommunications, and renewable energy systems. In contrast, alternating current (AC) oscillates and changes direction periodically, making it distinctly different from DC.

The other options do not accurately define DC. While option A refers to alternating current, option C describes a variable or fluctuating current, which is also not representative of DC. As for option D, while batteries are a common source of direct current, DC is not limited to being powered by batteries alone. Various other sources, including photovoltaic cells and fuel cells, can also produce DC. Thus, the correct characterization of direct current is its unidirectional flow.