What is the purpose of a back cap in gas tungsten arc welding?

The purpose of a back cap in gas tungsten arc welding is to insulate the electrical connections. In this context, a back cap is used to cover the end of the electrode holder, providing insulation that helps protect the welder from electrical shock and also prevents accidental grounding of the electrode. Proper insulation is crucial to ensure safety and functionality during the welding process.

While the other options may pertain to aspects of the welding process, they do not specifically describe the primary function of the back cap. Protecting the electrode and enhancing arc stability relate more to the welding process and equipment design rather than the specific role of the back cap. Similarly, adjusting gas flow is a function linked to the gas delivery system in welding, not the back cap itself. Thus, insulation of electrical connections is the most accurate description of the back cap's purpose.