In combination with an ADL DC power supply, the pulse generators SD 151 / SD 301 and SD 351 generate unipolar pulses with a reverse pulse for faster discharge of the cathode. In combination with reverse pulses, the extremely fast, fully automatic arc suppression reduces the arc energy by approx. 50 % – in comparison to a pulse generator without reverse pulse (SD 150 / SD 300). The generators work with a fixed frequency of 20 kHz. Thus, with an external signal generator, this frequency can be varied in a range of 1 kHz up to 40 kHz. Up to eight pulse generators can be interconnected for automatic synchronization via control cables. The new electronics contained in SD 151, SD 301 and SD 351 compensate for delay times, so that even if the high voltage outputs are connected in parallel, no master oscillator is necessary for exact synchronization.