A circuit is disclosed which minimizes the amount of tissue vaporized during a first half (positive half cycle) of an electrosurgical current cycle and minimizes the amount of current applied to tissue during a second half (negative half cycle) of the electrosurgical current cycle to control thermal spread. The circuit is preferably provided within an electrosurgical generator which is capable of controlling the amount of energy delivered to a patient during electrosurgery on a per arc basis.