This article discusses improvements in the efficiency, output power, and operational flexibility of MEDEA II, a double‐pulse electron beam accelerator at McDonnell Douglas Research Laboratories. A modified charging circuit, based on the triple‐resonance pulse transformer concept, was implemented on both of MEDEA II’s two stages. The output switches were modified to increase maximum output voltages, and a new, second output switch with asymmetric breakdown characteristics was developed. To avoid degradation of the second‐pulse output waveform at the diode, a keep‐alive circuit was installed. The effects of diode closure on double‐pulse operation are also discussed.