The DC-DC Converter provides clean 120Vdc power suitable for instrumentation and control networks or process equipment. For operation under the most harsh and demanding conditions, the unit is fully sealed and enclosed to protect against moisture, shock and vibration. Power from a battery or other source in the range of 9-36Vdc is converted to a 120Vdc output regulated to 2%. Input and output isolation is provided. The unit is designed with extremely rugged surge and transient suppression in addition to sustained over/under voltage protection. With a nominal nameplate rating of 30 Watts of output power, the DC-DC Converter has an efficiency rated at >91%.