The plug-in NSG 223 A of the mains interference simulator system NSG 200 generates high energy interference pulses, as occur when switching inductive or capacitive loads, or as produced by lightning flashes. The pulses are superposed symmetrically or asymmetrically on the line voltage or are available externally for component testing. The high pulse energy of approx. 2 Joules can destroy capacitors or semiconductors, or cause malfunctioning of thyristors and electronic circuits. Due to voltage flash-over on the test object interference can occur with rise times in the ns region. By means of the Variac and converting transformer depending on the setting of the amplitude control, the charging capacitor C0 can be charged to a maximum of lkV. A thyristor discharges C0, depending on the switch setting, directly into the line (symmetrically L2,L1/E). or the pulse is transformed to 3kI with the high voltage transformer and coupled in asymmetrically (12,Ll/E). For component testing the pulses are available without line voltage superposition at the QUT-PUI socket 1/3/5 kV. The pulse polarity can be reversed, also the rise time for standard tests 1.2/50 ps can be switched from approx. 300 ns to 1.2 jjs. The pulse repetition frequency is 1/8 of the line frequency. The pulse amplitude as well as the phase of the interference pulse are calibrated and can be continuously varied. The pulse can be directly triggered via the trigger input.