This paper presents the test results and simplified design method of a new type symmetrical resonant DC/DC converter. The realized converter operates in the frequency range of 30-300 kHz. This paper contributes the theoretical results of the resonant type DC/DC converters and shows the limits of their usage. The simulation results support the theory of the losing converter. The output voltage-current curve (Vo-Io) shows the typical features of the converter operation. This paper also deals with converters working with non ideal resonant circuit.