FIELD: welding processes and equipment. SUBSTANCE: power source for generating welding current in the form of pulse train with maximum current level includes inverter circuit with inlet connected to power source, first terminal with first electric polarity when inverter is energized; second terminal with second electric polarity when inverter is energized; and unit for controlling generation of OFF-signal for de-energizing inverter and taking off electric current from terminals for shifting current pulse to deenergized state. Circuit for switching power includes transistorized switch being in conductive state for passing current from first terminal at generation of first logic signal and being in non-conductive state at which electric current is not passing at generation of second logic signal. Welding power source includes pickup for measuring instantaneous current value; comparator for forming low current signal when instantaneous current achieves selected value that is significantly lower than maximum current level; circuit or program for generating second logic signal at low level current after forming OFF - signal for switching transistorized switch from conductive state to non-conductive state when welding current is practically equal to selected value. EFFECT: possibility for attenuating high electric current pulse until selected value before current pulse ending, lowered cost of power source for high-current welding. 39 cl, 9 dwg
