Experimental study of a nonlinear system in the presence of noise: The stochastic resonance

Noise in a dynamical system is usually regarded as a nuisance. However, in certain nonlinear systems the addition of noise in the system can give counterintuitive dynamics. An illustrative phenomenon is stochastic resonance (SR). In this paper we present, an experiment demonstrating stochastic resonance in a bistable electronic device: the tunnel diode. This experiment is suitable both as a lecture demonstration and for student investigations. We introduce the statistical properties of the noise and the physical picture of the SR phenomenon. We describe the experimental setup and present typical results.