What is the characteristic of Direct Current (DC)?

The characteristic of Direct Current (DC) is that it maintains a constant voltage and current. In a DC circuit, the flow of electric charge is unidirectional, meaning that the electrons move in a single direction only, which allows for a steady state of voltage and current over time. This is a fundamental property of DC, making it ideal for applications such as batteries, where a stable voltage is required for devices to operate effectively.

In contrast, other options reflect characteristics of alternating current (AC) or conditions that do not describe DC accurately. For example, the flow of electrons changing direction typically describes AC, where the current alternates back and forth. Alternating voltage is also a characteristic of AC, not DC. Lastly, the zero current flow would imply a non-operational state, which does not represent the consistent flow found in a DC circuit. Therefore, the defining feature of DC is its constant voltage and current, distinguishing it from other types of electrical currents.