What type of welding machine is required when using ER705-2 (mig/tig)?

• A. Constant voltage
• B. Constant current
• C. Variable voltage
• D. Portable transformer

Answer: (A)

Constant voltage power sources are used for MIG welding because they keep the arc voltage steady as the wire feed, travel speed, and arc length change. This stability is crucial for a smooth, consistent arc and uniform deposition when using ER705-2 in MIG/TIG applications. If a constant-current source were used, the arc voltage would fluctuate with changes in current, making the arc hard to control and the weld bead inconsistent. The other options don’t provide the same reliable arc control for a wire-feed process, as a fixed-volt/constant-current distinction beyond the CV capability is not the standard setup for this filler in MIG/TIG use.