Chaos in the Colpitts oscillator

In this work, we present experimental results and SPICE simulations of chaos in a Colpitts oscillator. We show that the nonlinear dynamics of this oscillator may be modeled by a third-order autonomous continuous-time circuit consisting of a linear inductor, two linear capacitors, two linear resistors, two independent voltage sources, a linear current-controlled current source, and a single voltage-controlled nonlinear resistor. The nonlinear resistor has a two-segment piecewise-linear DP characteristic. With the appropriate choice of parameters, the piecewise-linear circuit model has a positive Lyapunov exponent