The weld analyzer is an instrument for measuring and controlling the electric parameters of resistance welders, for example: spot welders, projection welders, butt welders, seam welders, single phase and 50Hz three phase welders. It is supplied and equipped with toroidal sensor and feeding cable. it checks the quality of the effected welds by comparing the measured parameters with sample values previously stored and signals any faulty weld (out of parameters) with a message on the display and an alarm contact. The measured RMS represents the average value during the whole weld. By this function it is possible to read on the display period by period the last welding sequence.