Various applications of the pulsed electric field technology (PEF), spanning from basic research to industrial scale, demand for different high voltage pulse generation concepts. The required pulse duration ranges from nanoseconds to milliseconds. Pulse amplitudes of several 100 V up to some 100 kV have to be generated. This article introduces the basics of pulse generator concepts based on capacitive energy storage. After illustrating the fundamentals of capacitor charging, capacitive pulse forming concepts for various applications will be introduced. Traditional concepts range from single capacitor discharging across transmission line based generators, pulse forming network generators up to multiple stage Marx generators for high energy transfer to material to be treated at high mass flow conditions. Switches are important components of pulse generators. Traditional gas discharge switches and semiconductor switches will be compared for generator implementations in the field of pulsed electric field assisted food processing.