Electronic circuits are dynamical systems. There is a long tradition to investigate electronic circuits using the emerging dynamical system theory since the 1930s with the contributions by Balthazar van der Pol [1] and Aleksandr Andronov’s school [2] to only quote the most well known. Henri Poincaré, who may be considered as one of the fathers of the dynamical system theory, investigated himself the equation governing a singing arc [3]. Later, books by Nicholai Minorsky [4] and Chihiro Hayashi, [5] were important in popularizing the dynamical systems approach in electronic circuits.
Early contributions to chaos by people investigating electronic circuits were reviewed in Ref. [6].