Microprocessor controlled, single phase, fan cooled power supply for MIG/MAG, TIG, MMA electrode, flux and arc welding plus brazing applications. Synergic operation gives efficient welding control and is particularly useful when welding aluminium, galvanised sheets, high strength steel and stainless steel. LED power read-out with push-button programming in conjunction with an encoder knob. The unit features regulation of post-gas and current down-slope time as well as control of AC balance and arc force. When TIG welding, the current can be set to change from one preset value to another using the torch button.