* Some non-linear [[Electrical Circuit|electrical circuits]] exhibit limit cycle oscillations,<ref>{{Cite journal|last=Ginoux|first=Jean-Marc|last2=Letellier|first2=Christophe|date=2012-04-30|title=Van der Pol and the history of relaxation oscillations: Toward the emergence of a concept|journal=Chaos: An Interdisciplinary Journal of Nonlinear Science|volume=22|issue=2|pages=023120|doi=10.1063/1.3670008|pmid=22757527|issn=1054-1500|arxiv=1408.4890|bibcode=2012Chaos..22b3120G}}</ref> which inspired the original [[Van der Pol oscillator|Van der Pol model]]. | * Some non-linear [[Electrical Circuit|electrical circuits]] exhibit limit cycle oscillations,<ref>{{Cite journal|last=Ginoux|first=Jean-Marc|last2=Letellier|first2=Christophe|date=2012-04-30|title=Van der Pol and the history of relaxation oscillations: Toward the emergence of a concept|journal=Chaos: An Interdisciplinary Journal of Nonlinear Science|volume=22|issue=2|pages=023120|doi=10.1063/1.3670008|pmid=22757527|issn=1054-1500|arxiv=1408.4890|bibcode=2012Chaos..22b3120G}}</ref> which inspired the original [[Van der Pol oscillator|Van der Pol model]]. |