An ultra-voltage gain dc-dc converter is proposed in this paper using an active impedance network with a single MOSFET switch. The proposed converter utilizes minimum components and achieves the ultra-gain with lower switch voltage stress. The general structure of an n-stage active switched impedance topology is presented, and the detailed operation of the basic converter configuration is discussed. The components of the converter are designed using proper mathematics, and a 200 W, 50 kHz, 650 V lab-scale hardware prototype is fabricated. The dynamic model of the converter is derived, and the transfer function v/d is presented. The testing of the 200 W prototype has been done, and the experimented waveforms are shown. Reduced components, lower voltage stress, ultra-voltage gain and single MOSFET are the major merits of the proposed converter; hence the converter has a potential application in high-voltage low power systems. Reduced Switch Voltage Stress Ultra-gain DC-DC Converter for High Voltage Low Power Applications