ABSTRACT
This chapter illustrates several methods to study the behavior of nonlinear circuits and systems are illustrated for memristors, and nanodevices based on deoxyribonucleic acid (DNA) or carbon nanotubes (CNTs). It presents the definition of describing function (DF) and its calculation, step by step, for a general nonlinearity. The DF for a general v–i characteristic was calculated and the final formula, with particular parameters, was used to derive the DFs for a memristor and for DNA and CNTs-based nanodevices. Future work could consider a time-varying DF to improve the modeling of frequency-dependent nanodevices such as the memristor; also, the design of nanodevices to synthesize particular v–i characteristics is an open problem. The chapter introduces the Lienard equation for series RLC circuits with nanodevices. Other types of nanodevices use the molecule of life or CNTs between a pair of electrodes. The general formula is applied to memristors, and DNA or CNTs-based nanodevices.
