Abstract: An improvement in an A.C. TIG welder for passing a current across an arc gap between a workpiece and a non-consumable electrode alternating between a first direction of arc current flow with the electrode negative and a second direction of arc current flow with the electrode positive. This type of welder comprises a transformer with a load voltage creating secondary winding in series with the arc gap and with a squaring circuit. The improvement involves a current control circuit connected in parallel with the arc gap wherein the control circuit has an energy storing capacitor, charging means for allowing the capacitor to charge rapidly according to the voltage across the arc gap tending to cause current flow across the gap in the second direction and a discharge means for controlling discharge of the capacitor across the gap in the second direction when the arc is created across the arc gap for current flow in the second direction.