Software packages such as Mathematica, Mathcad, or Matlab can be used to solve nonlinear differential equations, but in this paper the CAD tool DesignLab, a version of Windows PSpice, is used to achieve the same purpose. DesignLab is originally designed for electric and electronic circuits analysis and simulation. Corresponding to a given nonlinear differential equation, a so-called analog-computer setup or circuit is established. Integrators, summers, and inverters are normally implemented in the setup. Linear as well as nonlinear voltage controlled voltage sources are usually also needed in the setup. Option PSpice of DesignLab is then run to analyze the circuit and obtain the solution of the nonlinear differential equation. Numeric output of the solution is contained in a file which is available on the screen, or by using a printer. With the option Probe, we can view the solution as a curve with respect to time. The method can be readily extended to solve a system of nonlinear differential equations. Examples are given to illustrate the procedure for solving nonlinear and a system of nonlinear differential equations.
Proceedings of 2003 International Conference on Informations, Cybernetics, and Systems，頁965-968