Several international standards and norms apply to welding processes and the structure and features of welding machines and supplies. They contain definitions, instructions and restrictions for procedures and machine structures to increase the safety of processes and machines and to ensure the quality of products.

The arc needed in welding is a burst of electricity between the welding electrode and the weld piece. The arc is generated when a sufficiently great voltage pulse is generated between the pieces. In TIG welding this can be accomplished by trigger ignition or when the welded material is struck with the welding electrode (strike ignition).

Welding refers to the uniting or fusing of pieces by using heat and/or compression so that the pieces form a continuum. The source of heat in welding is usually an arc flame produced by the electricity of the welding power supply. Arc-based welding is called arc welding.