In this paper a low power (1.8 kW), high frequency (33 kHz), no-flight breadboard of Power Conditioning Unit (PCU) for arcjet application is described. The structure and the main electrical data of the PCU are presented, with particular car to the two fundamental hardware blocks: the start-up unit and the DC/DC converter for the arc supply. The PCU control is described too. Also the control description can be divided in two main blocks: the analog and the digital section. Finally, the start-up control technique is described. After the review of the technical characteristics of the PCU, preliminary test results on arcjet simulator are presented