Thermal noise in nonlinear resistive devices and its circuit representation

The major developments, since the Nyquist theorem, in the study of thermal noise in linear and nonlinear dissipative devices are briefly summarized. Then the author´s recently established theorem for calculating thermal noise in biased, near-equilibrium, nonlinear resistive devices is discussed, and examples of its use are presented. Based on the theorem, an equivalent circuit model for representing the noise in such devices is proposed, and is applied to analyze the behavior of nonlinear resistors in such applications as heat engines and refrigerators.