What is the term for an electric current that changes direction at regular intervals?

An electric current that changes direction at regular intervals is called alternating current. This type of current is characterized by its ability to periodically reverse its flow, which is typically represented by a sinusoidal waveform. The regular change in direction allows alternating current to be efficiently transmitted over long distances, making it the standard for power distribution in homes and industries.

In contrast, options such as direct current refer to a flow of electric charge that remains constant in one direction, which is not the case for the question asked. Pulsating current, while it does fluctuate, does not imply a systematic reversal in direction like alternating current. Static current refers to stationary electric charges and does not involve any current flow at all, thus making it unrelated to the context of the question.