Final answer:
The type of current that changes its direction periodically is Alternating Current (AC). Unlike Direct Current (DC), AC increases to a certain value, decreases back to zero, then increases again in the opposite direction, thus providing a regular reversal in its flow.
Step-by-step explanation:
The electric current that travels in one direction for a period of time, then reverses its direction for a period of time, is called Alternating Current (AC). Unlike Direct Current (DC), which is the flow of electric charge in only one direction and does not change, an Alternating Current reverses its direction at regular intervals of time.
For example, the residential and commercial power that we commonly use are Alternating Current. This is because it increases up till a maximum current value, decreases back to zero, then increases again, but in the opposite direction. This alternate reversal of the current's direction is performed repeatedly.
Learn more about Alternating Current