Leading chaos to order for a nonlinear circuit system

A third-order circuit system with nonlinear negative capacitance is studied. The dynamical equation and state equation of the system are established. By the phase portraits, the motions of the system are studied under the definite parameters. And by bifurcation diagram, the route from periodic motion to chaos is studied under the presented system parameters. Two methods are constructed to control the chaos of a third-order circuit system with nonlinear negative capacitance. One is adding an adjustable resistance to the system and the other is an improved delay continuous nonlinear feedback method. The phase plane portraits and bifurcation diagram of the controlled system are obtained. The advantages of the two controlled methods are that the collect of the control signals are simple and can put on any time and the chaotic system can be asymptotically stabilized to equilibriums with small control. The orbits of the system can be controlled by these two methods according to our target.