Abstract: A fast transient simulator (71) of SOI MOS circuits uses fast and accurate SOI transistor table models (FIGS. 18, 19). The simulator uses a representation of a circuit with partitions (130). Each of partitions (130) is simulated separately for a short time step by numerically solving differential equations describing its transient behavior. Behavior of the whole circuit is simulated in an event driven way where each event corresponds to an integration time step for each partition. Instead of body voltage (Vy), the simulator (71) implements a transformation and uses body charge (Uy) as an independent variable in order to obtain high accuracy and high speed of simulation. Construction of SOI transistor table models (FIGS. 18, 19) results in speed and accuracy enhancements. This transformation allows the reduction of the number of table dimensions exploiting the fact that SOI transistor backgate capacitance is approximately constant.