Abstract: A simulation is carried out in a computer system in which a circuit description of an electrical circuit having a plurality of nodes and a plurality of circuit elements is present. First, voltage values and/or current values at the nodes of the electrical circuit are calculated in a selected time interval using table-based models for the circuit elements. From these voltage values and/or current values, simulation times tn are determined in the time interval [tstart; tstop] under consideration at which system equations of the circuit description are determined and calculated. These system equations describe the circuit elements using physical formulas and do not describe the dynamic effects of the circuit elements using differential equations.

Abstract: A simulation apparatus for a system has at least one analog and at least one digital element, in particular an electronic system. The simulation apparatus has an apparatus for solving differential algebraic equation systems based on a one-step method for automatically producing a data record with a simulation event. A detector is provided for automatically determining that a threshold value has been exceeded within one time step in the simulation event. The detector determines whether the simulation event is greater at the end of the respective time step than a predetermined tolerance of the respective threshold value. The detector automatically reduces the time step if the tolerance is exceeded, until the tolerance is undershot, in order to determine the point at which the threshold value is exceeded. A transformation device uses values calculated previously for this purpose. It is thus possible to simulate mixed digital-analog systems particularly efficiently.