Rich non-linear dynamics in minimal-silicon traditional oscillators

Rich non-linear dynamics in minimal-silicon traditional oscillators 

Lambert Schomaker / March 2026

(post-hoc re-recording of a lecture given in the 'CogniGron@Work' series on 23rd of March 2026) 

Abstract

Active electronic components such as the triode thermionic valve were traditionally very expensive. The challenge at the start of the previous century was to implement oscillators in a cost-effective manner, i.e., with only one active component and a number of passive components. From this predicament, the patents for the Colpitts and Hartley oscillators emerged. These extremely simple circuits can also be constructed with a single modern transistor. Either way, they exhibit very interesting non-linear behaviors, far beyond the boring sine wave. In this presentation I will give practical examples (circuits, sound samples) to illustrate the richness of behaviors of these circuits, especially if coupled or subjected to a slowly varying resistance parameter value. Complexity from simplicity is always intriguing and may elicit new ideas for solutions in neuromorphic computing.

Video of presentation, with circuit examples (LTSpice) and audio samples showing non-linear and chaotic behavior of the Hartley oscillator. With transcript (.pdf).