GMAW power supply combination is typically described as which?

• A. Direct current, constant voltage
• B. Direct current, constant current
• C. Alternating current, constant voltage
• D. Alternating current, constant current

Answer: (A)

GMAW uses a direct current power supply operated as constant voltage. The arc length and stability are controlled by keeping the arc voltage at a steady set value, while the current naturally adjusts based on the wire feed speed and welding conditions. This setup makes the arc more stable across different positions and speeds, which is essential for smooth, consistent transfer of metal. Alternating current isn’t typical for GMAW, and a constant-current source would make maintaining a steady arc length harder, since the voltage would vary with changes in the arc.