Which unit is used to measure welding current?

• A. Amperes
• B. Volts
• C. Ohms
• D. Watts

Answer: (A)

Current is the flow of electric charge through a circuit, and its size is measured in amperes (A). In welding, the welding current is the amount of current delivered to the arc; higher amperage produces more heat, increasing penetration and bead size. This unit distinguishes from volts, which measure potential difference; ohms, which measure resistance; and watts, which measure power (volts times amperes). The welding machine adjusts this current to achieve the desired weld characteristics.