A pulse generator circuit arrangement for the search for insulation faults in IT networks includes a rectifier circuit for transforming an IT network voltage into a DC intermediate circuit and switching elements having a trigger signal input for switching on and off a DC intermediate circuit voltage. A circuit device downstream of the switching elements generates a pulsed current to be supplied to the IT network. The circuit arrangement includes a control and evaluating logic for determining the insulation resistance of the IT network and also a circuit device for generating the pulsed current, which is formed as a current regulating device and allows a dynamic adjustment of the pulsed current depending on the determined insulation resistance.