An arc welding power source that maintains voltage at a relatively constant level, regardless of fairly large changes in current caused by caused by changes in electrode extension. This type of power source is used primarily with processes that employ a continuously fed wire electrode. These include Gas Metal Arc Welding (GMAW), Flux Cored Arc Welding (FCAW), and Submerged Arc Welding (SAW). Constant voltage power sources have a flat volt-ampere curve. See also Welding Power Source and Constant Current Power Source.