Consider a dynamic circuit containing nonlinear resistors, the other elements being linear. Each nonlinear resistor is replaced by a set of equivalent sources which are current or voltage dependent. The parameters of these sources are corrected iteratively. In order to find the new controlling voltages (currents) linear sinusoidal problems are solved for source harmonics. The convergence of this iterative procedure is proved. This method gives correct results for strongly nonlinear circuits driven by modulated signals, unlike the harmonic balance method. An example is given for illustration.

Keywords: Steady state, Nonlinear circuit analysis.