In this paper, the homotopy perturbation method HPM, is employed to obtain an approximate solution for the nonlinear differential equation which describes an alternating current RC circuit, taking into account the effect of a nonlinear resistance on the current. In order to compare this solution, the problem is solved using two homotopy approaches: the standard HPM method and a modified version of HPM. From these methods, two different approximate solutions are obtained. Comparison with exact solution shows that the HPM method is extremely efficient if the initial guess is chosen adequately.