Which statement describes DC voltage?

DC voltage, or direct current voltage, is characterized by its constancy in both strength and polarity. This means that when you measure DC voltage over time, the voltage level remains steady without any fluctuations. The positive and negative charges do not alternate as they do in alternating current (AC) systems; instead, the current flows in one direction only.

Understanding this concept is crucial because many electronic devices, such as batteries and DC power supplies, rely on a stable source of voltage to operate effectively. The stability of DC voltage allows for consistent performance in applications including electronics, signals, and various types of power supplies.

In contrast, other types of voltage can exhibit varying characteristics over time, which is why they are not representative of DC voltage. Fluctuation in strength and polarity indicates AC voltage, while the possibility of varying only in strength or changing direction periodically further reinforces that these are properties associated with AC systems, not DC.