What type of current flows in one direction only?

Direct Current (DC) is characterized by the flow of electric charge in a single direction. This type of current is often used in battery-operated devices and electronic circuits, where a steady voltage is required for operation. In a DC circuit, the voltage remains constant over time and the current flows consistently, making it ideal for applications such as powering small electronic devices, charging batteries, and in various components within HVACR systems that require reliable and uninterrupted power.

In contrast, Alternating Current (AC) changes direction periodically, making it different from DC. AC is commonly used in households and businesses for its ability to be transmitted over long distances efficiently. Pulsating Current is a form of current that varies in magnitude but does not change direction consistently, which also distinguishes it from the steady flow of DC. Reactive Current, on the other hand, typically refers to currents associated with inductive and capacitive loads that do not contribute to net energy transfer but are necessary for the functioning of devices like motors and transformers.

Therefore, the clear distinction of DC flowing in one direction only makes it the correct choice for this question.