A welding power source comprising: a power conversion circuit configured to convert an input current to an output current; a controller; and characterised by the following features: a main bridge circuit operatively connected to the power conversion circuit having at least two switching transistors (311, 312) configured to switch a direction of the output current through a low impedance welding output circuit path operatively connected to welding output of the welding power source at the command of the controller; and an auxiliary bridge circuit connected in parallel to the main bridge circuit having at least two switching transistors (313, 314) and at least one resistor, the auxiliary bridge circuit configured to introduce a high impedance path between the power conversion circuit and the welding output circuit path at the command of the controller, wherein the auxiliary bridge circuit follows the polarity of the main bridge circuit and, at certain times, interrupts the main bridge circuit to introduce the high impedance path, wherein the main bridge circuit is configured as a half bridge circuit or as a full bridge circuit, in that a resistance value of the at least one resistor is preferably less than 2 ohms, and the auxiliary bridge includes one of the at least one resistor, as a shared resistor, between two alternate switch transistors (313, 314) of the at least two switching transistors in a common current path. a power conversion circuit configured to convert an input current to an output current; a controller; and characterised by the following features: a main bridge circuit operatively connected to the power conversion circuit having at least two switching transistors (311, 312) configured to switch a direction of the output current through a low impedance welding output circuit path operatively connected to welding output of the welding power source at the command of the controller; and an auxiliary bridge circuit connected in parallel to the main bridge circuit having at least two switching transistors (313, 314) and at least one resistor, the auxiliary bridge circuit configured to introduce a high impedance path between the power conversion circuit and the welding output circuit path at the command of the controller, a main bridge circuit operatively connected to the power conversion circuit having at least two switching transistors (311, 312) configured to switch a direction of the output current through a low impedance welding output circuit path operatively connected to welding output of the welding power source at the command of the controller; and an auxiliary bridge circuit connected in parallel to the main bridge circuit having at least two switching transistors (313, 314) and at least one resistor, the auxiliary bridge circuit configured to introduce a high impedance path between the power conversion circuit and the welding output circuit path at the command of the controller, wherein the auxiliary bridge circuit follows the polarity of the main bridge circuit and, at certain times, interrupts the main bridge circuit to introduce the high impedance path, wherein the main bridge circuit is configured as a half bridge circuit or as a full bridge circuit, in that a resistance value of the at least one resistor is preferably less than 2 ohms, and the auxiliary bridge includes one of the at least one resistor, as a shared resistor, between two alternate switch transistors (313, 314) of the at least two switching transistors in a common current path.