The present invention is directed to a MIG welding machine having a 115 volt inverter. Incorporation of the 115 volt inverter into the MIG welding power source reduces the weight of the power source thereby increasing its portability. The power source may include a power factor correction circuit to provide a near-unity power factor such that output power of the inverter is more efficiently provided. Additionally, the 115 volt inverter is constructed such that for short periods of time, the inverter may output power at a level that exceeds its power rating.