Abstract: A pulse generator for metal machining by electric discharges, comprising a primary current circuit for producing and transmitting pulse forms to a pair of electrodes. A voltage and/or current source is arranged in the low-ohm and low-loss primary current circuit, the voltage of which has a value which is only that much greater than the operating voltage of the pulses flowing through the spark gap as is needed to positively overcome the voltage losses occurring in the primary current circuit. A signal generator produces a signal corresponding to the desired current pulse shape or form. A comparator, which has a switch arranged in the primary current circuit for regulating the current flow in such primary current circuit, controls the current flowing through the primary current circuit, as a function of the desired pulse form produced by the signal generator and a magnitude of the current flowing in the primary current circuit which is tapped-off by a measuring feeler.