1. An automatic circuit that measures electrosurgical generator output and controls it in accord with impedance between activated bipolar electrodes attached thereto, comprising: an electrosurgical generator; a pair of spaced apart bipolar electrodes able to move together and apart for contacting tissue therebetween connected to the electrosurgical generator; a voltage monitor connected in parallel with the pair of bipolar electrodes for measuring an instantaneous voltage variation therebetween and generating proportional signals relative to each measured instantaneous variation of voltage; a current monitor connected in series with the pair of bipolar electrodes for measuring an instantaneous current variation therebetween and generating proportional signals relative to each measured instantaneous variation of current; a first calculator attached to the voltage monitor and the current monitor for receiving the proportional signals to find by in effect dividing the voltage by current for generating proportional signals relative to the instantaneous indications of short circuit impedances between the pair of bipolar electrodes; a second calculator attached to the voltage monitor and the current monitor for receiving the proportional signals to find by in effect dividing the voltage by current for generating proportional signals relative to the instantaneous changes in impedances between the pair of bipolar electrodes for other than short circuit impedance; a first comparator connected to receive the proportional signals from the first calculator, assess these proportional signals against a first reference and provide instantaneous signs identifying short conditions between the pair of bipolar electrodes; a second comparator connected to receive the proportional signals from the second calculator, assess these proportional signals against a second reference and provide assessments of the instantaneous signs identifying changes in impedance between the pair of bipolar electrodes; and a logic analyzer connected to receive the signs and assessments of the first and second comparators and to control the electrosurgical generator for evaluating the signs and assessments to permit the starting, operating or stopping of the electrosurgical generator based on the evaluation.