Narrow Results

In this paper, we show that the dynamics of any memristor circuits can be simulated by a corresponding "dual" nonlinear RLC circuit where the memristor is substituted by a nonlinear resistor. They are in one-to-one correspondence, that is, they are duals of each other. We also propose a method for synchronizing these dual dynamic nonlinear circuits. We next define memory elements which can be characterized by charge and flux. The memory-element circuits can also be simulated by their corresponding dual nonlinear RLC circuits. We then define 2-terminal elements which are characterized by complementary pair of signals, and study them from the view point of one-to-one correspondence. We finally show an example of 2-terminal elements such that the terminal voltage and current are identical, and their time-derivatives of any order are also identical, however, their time-integrals are different. That is, these 2-terminal elements are in one-to-one correspondence except for the time-integral signals.

Memristor, the missing fourth passive circuit element predicted forty years ago by Chua was recognized as a nanoscale device in 2008 by researchers of a H. P. Laboratory. Recently the notion of memristive systems was extended to capacitive and inductive elements, namely, memcapacitor and meminductor whose properties depend on the state and history of the system. In this paper, we use fractional calculus to generalize and provide a mathematical paradigm for describing the behavior of such elements with memory. In this framework, we extend Ohm's law to the generalized Ohm's law and prove it.

In this paper, we show that parasitic elements have a significant effect on the dynamics of memristor circuits. We first show that certain $2$-terminal elements such as memristors, memcapacitors, and meminductors can be used as nonvolatile memories, if the principle of conservation of state variables hold by open-circuiting, or short-circuiting, their terminals. We also show that a passive memristor with a strictly-increasing constitutive relation will eventually lose its stored flux when we switch off the power if there is a parasitic capacitance across the memristor. Similarly, a memcapacitor (resp., meminductor) with a positive memcapacitance (resp., meminductance) will eventually lose their stored physical states when we switch off the power, if it is connected to a parasitic resistance. We then show that the discontinuous jump that circuit engineers assumed to occur at impasse points of memristor circuits contradicts the principles of conservation of charge and flux at the time of the discontinuous jump. A parasitic element can be used to break an impasse point, resulting in the emergence of a continuous oscillation in the circuit. We also define a distance, a diameter, and a dimension, for each circuit element in order to measure the complexity order of the parasitic elements. They can be used to find higher-order parasitic elements which can break impasse points. Furthermore, we derived a memristor-based Chua’s circuit from a three-element circuit containing a memristor by connecting two parasitic memcapacitances to break the impasse points. We finally show that a higher-order parasitic element can be used for breaking the impasse points on two-dimensional and three-dimensional constrained spaces.

A smooth curve model of meminductor and its equivalent circuit have been designed, on the condition that the meminductor is commonly unavailable. The equivalent circuit can be used for breadboard experiments for various application circuit designs of meminductor. Based on the meminductor, a new chaotic oscillator is proposed. The dynamical behaviors of the oscillator are investigated, including equilibrium set, Lyapunov exponent spectrum, bifurcations and dynamical map of the system. Particularly, the amplitude controlling is analyzed and coexisting attractors are found for conditions of different parameters. Furthermore, the experimental results are given to confirm the correction of the proposed meminductor model and the meminductor-based oscillator.

Memory elements, including memristor, memcapacitor, meminductor and second-order memristor, have been widely exploited recently to realize circuit systems for a broad scope of applications. This paper introduces a phasor analysis method for memory elements to help with the understanding of the complex nonlinear phenomena in circuits with memory elements. With the proposed method, all different memory elements could be described in a unified form and the series-connected circuit with memristor, memcapacitor, meminductor and second-order memristor could be simply modeled as one variable ${Ż}_M$. Thus, the phasor vectors provided a way to conveniently calculate the $v$–$i$ relation of different memory elements and to clearly understand the similarities and differences between all memory elements. Then some interesting phenomena were introduced when combining different memory elements. Moreover, a specific ${Ż}_M$ with certain $v$–$i$ relations could be easily obtained with the method. And through the inverse calculation, the specific ${Ż}_M$ could be decomposed to a certain combination of memory elements. Meanwhile, the parameters of ${Ż}_M$ in the phasor domain were analyzed. Furthermore, the frequency characteristic for a $R_M{L}_M{C}_M$ circuit could be easily analyzed with the method and a particular series resonance was introduced.

A multistable local active meminductor emulator is proposed in this paper. The mathematical model of the emulator circuits is established. Different periodic stimuli are applied to the presented emulators and coexisting stable pinched hysteresis loops are obtained. The results obtained by experimental equips are consistent with the theoretical analysis, which indicates that the proposed emulators can work as a meminductor.