Investigation of stochastic resonance (SR) near homoclinic bifurcation in a unijunction transistor (UJT) relaxation oscillator

TL;DR

This paper investigates how stochastic resonance enhances weak signals in a UJT relaxation oscillator near homoclinic bifurcation, combining simulations, experiments, and mathematical modeling.

Contribution

It introduces a mathematical model based on UJT characteristics and demonstrates stochastic resonance near bifurcation points through combined simulation and experimental validation.

Findings

SR observed near homoclinic bifurcation

Normal variance and SNR quantify SR effects

Mathematical model replicates experimental results

Abstract

A P-spice simulation followed by an experiment with a unijunction transistor (UJT) has been carried out to investigate stochastic resonance (SR) in which the response of a nonlinear system to a weak periodic input signal is amplified by an optimum level of noise. The experiments were carried out in the vicinity of homoclinic bifurcation and the quantification of SR has been done by normal variance (NV) and signal to noise ratio (SNR) techniques. We have also developed a tentative mathematical model based on the current-voltage characteristic of the UJT and obtained a second order differential equation that was solved using MATLAB to yield a response similar to the one observed experimentally.