What term refers to the voltage present across the welding arc?

The term that refers to the voltage present across the welding arc is known as arc voltage. This voltage is a critical parameter in the MIG welding process as it directly impacts the characteristics of the weld. Arc voltage affects the arc length, stability, and overall heat input to the workpiece. A proper arc voltage ensures adequate penetration and bead shape, while an incorrect arc voltage can lead to poor weld quality.

Understanding arc voltage is essential for welders, as it helps in troubleshooting issues related to arc stability and weld appearance. The other options, while related to electrical concepts, do not accurately describe the specific voltage across a welding arc, making arc voltage the correct term for this particular measure in MIG welding.