Difference between supple and stiff non-linear elements

Abstract

In the previous paper a need for a distinction of non-inert (supple) and inert (stiff) non-linear elements has been introduced. There it has been shown, that an influence of an external phenomenon that evokes changes of parameters of the non-linear element can be explained using two kinds of ideal elements (e.g., two resistors) with the same static characteristic function: E = Fs(C), where E is an effect and C is a cause. These two ideal elements are: - an ideal non-inert element (an ideal supple element), in which a change of a parameter occurs immediately with the change of the cause; - an ideal inert element (an ideal stiff element), in which the change of the parameter does not occur after the change of the cause until time t -> . In this paper an example of a simple circuit with a non-linear resistor, supplied with a sinusoidal voltage, is considered. A so-called "capacitance effect" can be stated on the basis of analysis of the equation describing this circuit. For voltage frequencies greater than 10 Hz, the circuit is a quasi-linear system, as for a sinusoidal voltage the current waveform is also sinusoidal. However, for frequencies lower than 5 Hz, the current changes in time accordingly to a non-linear characteristic function of this resistor, thus the current is no more sinusoidal. The first current harmonic is then shifted ahead of the voltage as if the circuit contained a capacitor.