In a constant-voltage welding machine, increasing electrode extension affects current by decreasing it.

In a constant-voltage welding machine, increasing electrode extension affects current by decreasing it.

• A. Current decreases
• B. Voltage decreases
• C. Current increases
• D. Wire feed rate increases

Answer: (A)

In a constant-voltage welding machine, the voltage is kept at a fixed level. Increasing electrode extension lengthens the arc, which increases the arc’s resistance. With the voltage held constant, Ohm’s law (I = V/R) means the current must drop as resistance rises. So the current decreases when you increase electrode extension.

In a constant-voltage welding machine, the voltage is kept at a fixed level. Increasing electrode extension lengthens the arc, which increases the arc’s resistance. With the voltage held constant, Ohm’s law (I = V/R) means the current must drop as resistance rises. So the current decreases when you increase electrode extension.