What is the rate at which alternating current makes a full change in direction called?

The term that describes the rate at which alternating current (AC) makes a full change in direction is known as frequency. Frequency is measured in hertz (Hz), which indicates how many cycles of alternating current occur in one second. In the context of welding, particularly with processes like Gas Tungsten Arc Welding (GTAW) that may use AC for materials like aluminum, understanding frequency is crucial as it affects the arc stability, heat input, and overall quality of the weld.

While voltage refers to the electrical potential difference and wattage relates to the power consumed in the circuit, they do not directly describe the directional changes of the current. Cycling rate, while a similar concept, is not the conventional term used in electrical engineering to define this specific aspect of alternating current. Thus, frequency is the correct choice, as it accurately captures this fundamental characteristic of AC electrical systems.