Abstract: Disclosed is a variable polarity power supply for arc welding that quickly switches between polarities in order to more easily re-establish the arc. The variable polarity power supply includes a current-limited boost circuit for providing increased open circuit voltage to re-establish the arc, while limiting the re-establishment current. The variable polarity power supply is particularly suitable for computer-controlled welding applications because it periodically restarts the arc in either direction without using high frequency radiation, and provides quick switching times along with a low reverse current to reduce the heat in the torch, thereby increasing the longevity of the torch.