“…This approach for analysis of nonlinear systems is easily found in several classic books [Ogata, 1970;Slotine & Li, 1991;Khalil, 1996;Glad & Ljung, 2000], consisting of an extension of linear techniques based on the concepts of the frequency response in order to verify effects of certain nonlinearities on a feedback dynamic system. The analysis by describing functions allows to predict stability and the possible existence of limit cycles [Ogata, 1970;Oliveira et al, 2012] and chaotic behavior, which can be interpreted as an interaction between limit cycles and equilibrium points [Genesio & Tesi, 1991;Neymeyr & Seelig, 1991;Genesio & Tesi, 1992;Savacı & Günel, 2006]. The transfer function of the linear part of Chua's circuit between the output x and the input u (see Fig.…”