The usage of high voltage discharge in liquid has many technological applications. For realization of high voltage pulse discharge in liquid are used circuits with two discharge gaps, and one of them functions as a controllable high voltage switch. At capacitive energy storage and considering the parasitic inductances the discharge pulse most often has periodically attenuating character. The current work is dedicated to experimental study of high voltage discharge in a circuit with two discharge gaps with the usage of a controllable air discharger - trigatron. On the basis of the received results is performed analysis and is created a model of the resistance change at discharge in time, regarding the capacitance of the capacitor battery and the voltage, which it is charged to.