GMAW typically uses what power supply?

• A. Direct current with constant voltage
• B. Direct current with constant current
• C. Alternating current with constant voltage
• D. Direct current with pulsed current

Answer: (A)

GMAW relies on keeping the arc voltage essentially fixed while allowing the current to adjust with welding conditions. A direct-current power supply set to constant voltage provides that stable arc length, which is crucial for a smooth, continuous weld and consistent shielding gas coverage. The wire feed and hand position cause changes in current, but the voltage stays steady, helping to maintain a stable arc and predictable heat input. While there are variations like pulsed or constant-current setups for special cases, the typical GMAW setup uses direct current with constant voltage.