An excitation of super large aperture CO₂ - a n d N₂ O-lasers places demanding and unusual constraints on the pulsed power supply. Stable discharges with interelectrode gaps as large as g >70 cm were achieved [1, 2] using pulsed power supplies [3] that satisfy specific requirements imposed by volume preionization and discharge ignition. The supply must initially apply a quasi-dc or slow-rise voltage to effect preliminary filling of the gap with electrons from an auxiliary discharge, followed by application of a controlled rise voltage to ignite a self-sustained volume discharge (SSVD). A coupled particle kinetics-equivalent circuit model has been developed to simulate discharge behavior for the various pulsed power configurations. Our computational results are compared with experiments involving super large aperture, huge volume devices [1-4].