Abstract: In the present paper,we investigate a class of nonlinear oscillation equations inelectrical engineering by using the modified Krylov-Bogolyubov method presentedin[1]. We obtain quantitatively ihe parameier range for the existence of a limit cycleand the amplitude of the limit cycle,and find that the limit cycle is unstable. All theresults agree entirely with the known results given by qualitative analysis, and henceconfirm the effectiveness of the above-mentioned asymptotic method

Key words: modified Krylov-Bogolyubov method, nonlinear oscillation, limit cycle, asymptotic analysis