Main components of harmonic solutions of nonlinear oscillations

If second order non-autonomous circuit with damping satisfies certain conditions, the oscillations should contain two components, the self-excited and forced oscillations. This paper, on the theoretical basis of power balance, finds the critical value of this condition. With regard to non-autonomous circuits with no damping, active power can keep balance under any situations. The two oscillation components can simultaneously exist unconditionally. Taking nonlinear conservative system with excited source as example, this paper demonstrates that the circuit can produce chaos in all probability.