A prototype Helmholtz–Thompson nonlinear oscillator

Abstract

A prototype electronic (analog) circuit has been built to mimic a nonlinear oscillator proposed a century ago by Helmholtz in order to account for combinational tones in the drumskin, and more recently by Thompson to account for ship stability to waves in windy situations and its potential and eventual capsize. Besides a careful discussion of elements and their expected performance, several tests have been used to assess the reliability of the prototype.