Abstract: With a numerical method, LC and RC filter circuits were used to the nonperiodic signal filtering analyses in DC power output voltage. By applying the method of numerical solution of differential equation, the numerical recursive solution of circuit differential equations could be obtained, thus, numerical models of circuits could be established. The numerical models could be used to the quantitative analysis of nonperiodic signal. The defects of LC and RC filter circuits in DC power output voltage filtering were indicated, LRC filter circuit was introduced, and numerical simulation results show that this circuit can overcome the defects of LC and RC filter circuits, thus, ripple and noise can be mostly filtered. It’s proposed that LC and RC filter circuits should be replaced by LRC filter circuit in the practical application of DC power output voltage nonperiodic signal filtering.

Key words: LC filter circuit, LRC filter circuit, nonperiodic signal, numerical model, numerical analysis