The operation of Pichugin pulse generators (named after their Russian inventor) is studied. A set of equations for a one-stage generator enables us to point up the important frequency properties of the magnetic core transformer. An analytical and numerical study of a three-stage generator is performed. Improvements, concerning the voltage gain, are suggested; the consequences on the rise time value are analysed. A new conception method, based on compensated and asymmetrical stages, is proposed. It is a compromise solution to decrease the rise time value and to increase the voltage gain. By using this structure, the realization of a 120 kV, 145 ns rise time three-stage pulser is proposed; its operating at a frequency greater than 1 kHz is studied.