Threshold instabilities in nonlinear self-excited oscillators

Abstract

We present the results of a systematic study of threshold instabilities in a Wien bridge oscillator. The dynamical circuit equations can be cast into a time-dependent Ginzburg-Landau form where the order parameter is the complex zero-dimensional amplitude of the oscillatory voltage. In this context we have been able to simulate behavior which in classical theory is characteristic of first-order, second-order, and tricritical phase transitions, and have measured the associated threshold properties.