Penetration in a weld is primarily influenced by which electrical quantity in the circuit?

• A. Voltage
• B. Amperage
• C. Resistance
• D. Inductance

Answer: (B)

Penetration is driven by the heat delivered to the weld zone. That heat comes mainly from the welding current. When you increase the amperage, more energy is put into the arc and the molten pool, melting the base metal deeper and producing greater penetration. Voltage mostly affects the arc length and stability, which changes how heat is distributed, but it doesn’t control depth as directly as current. Inductance and circuit resistance influence how the current changes and how efficiently heat is generated, but the factor most directly adjustable to control penetration is the amperage.