Final answer:
Dig control in the welding circuit is activated when the load voltage drops below a certain threshold.
Step-by-step explanation:
In welding circuits, dig control is a feature that controls the amount of current supplied to the electrode for better arc stability. It comes into play when the load voltage is below a certain threshold.
For example, let's say the load voltage is set at 50 volts. If the load voltage drops below this value, the dig control would adjust the current to stabilize the arc. This is important because a stable arc is necessary for successful welding.
So, to answer your question, dig control only operates in the welding circuit when the load voltage is below the set threshold, which is typically determined by the specific welding machine being used.