What is the name for a current that flows only in one direction?

Direct current, or DC, is the term used to describe an electrical current that flows consistently in one direction. This characteristic is fundamental to many electronic devices, as it provides a stable and constant voltage that powers circuits and components effectively. For instance, batteries produce direct current, which is essential for a wide range of applications from small electronics to larger systems.

Alternating current (AC), in contrast, periodically reverses direction, changing the polarity of the voltage. This type of current is commonly used in homes and businesses for its ability to efficiently transmit power over long distances. The other options, such as normal current and smooth current, are not recognized terms in electrical engineering or physics, which makes them less applicable to the question.