FIELD: processes and equipment for electric arc welding, possibly in different branches of industry. SUBSTANCE: apparatus operates at using curve of first signal for controlling short-circuiting stage and next curve of second signal for controlling arc welding. Apparatus includes comparator for generating signal of electric arc when short-circuiting stage is completed and controller for switching apparatus for electric arc welding from controlling mode by means of curve of first signal to mode for controlling by means of curve of second signal in response to above mentioned electric arc signal. EFFECT: accurate control of heating welding bath during welding procedure, operation of power source in range of voltage change. 20 cl, 6 dwg
