A self-excited oscillator (in English: self-excited oscillator) is a feedback control system that determines the oscillation frequency through its own tuning circuit [1]. It includes types such as low-frequency oscillators, intermediate-frequency oscillators, and bistable oscillators. Its principle involves changes in the position of the closed-loop poles. When the system is in a nonlinear state, self-excited vibration can be achieved through optical-mechanical coupling or adjustment of circuit parameters [2-3].
This system consists of an amplification circuit, a positive feedback network, and a frequency-selective network, meeting the oscillation conditions of phase balance and loop gain AF ≥ 1. In typical applications, the Wien bridge oscillation circuit determines the frequency through RC components, and is combined with bidirectional voltage stabilizing diodes to achieve amplitude stabilization [3]. Some new oscillators use liquid crystal elastic body (LCE) fiber springs, and control the vibration behavior by adjusting the spring stiffness ratio or light intensity [2].