Abstract: Recurrence relations of the initial voltages across the primary capacitor between adjacent pulses are derivated based on the sequence processes of discharge and recharge of the primary capacitor in repetitive mode for a compact accelerator. The equation of the initial voltage across the primary capacitor in steady state is obtained. And the transition time or the number of the transition pulses between the unsteady state and the steady state can be calculated. The condition, under which the charge thyristor switch’s turn-on time is independent of the gas spark switch’s breakdown voltage, is theoretically discussed and experimentally obtained. Furthermore, the corresponding methods and steps are presented to guide the experiments. From the theoretical analyses and experimental investigati