Synchronization control between two Chua's circuits via capacitive coupling

Nonlinear circuits can generate a variety of oscillations by setting appropriate parameter regions, and periodic oscillation can present distinct periods in the sampled time series for observable variables while chaotic oscillation shows multiple modes in the output variables. Resistor-based voltage coupling benefits the synchronization approach between chaotic circuits even one coupling channel is activated, while consumption of Joule heat in the coupling resistor is inevitable during the realization of synchronization. Complete synchronization is often detected between identical circuits while phase synchronization is mainly reached between non-identical circuits. In this paper, two identical Chua circuits are connected by a capacitor, which the capacitance can be feasibly modulated to support synchronization realization. The mechanism is that the electric field in the coupling capacitor is changed by continuous charge and/discharge on the capacitor plates and energy flow exchange is enhanced to stabilize synchronization between the two chaotic circuits. From physical and experimental view, the capacitance values of coupling capacitor can be modulated by changing the distance and dielectric media between the capacitor plates, thus the coupling intensity is adjusted to change the ability of field energy pumping and exchange. It is found that this kind of electric field coupling can regulate the synchronization stability between dimensionless chaotic systems by applying scale transformation on the chaotic circuits. However, synchronization cannot be stabilized between two nonidentical Chua circuits with different parameter regions even when the coupling intensity is increased greatly. The same discussion is also verified in the circuits built on Multisim. As a result, capacitor coupling via one channel can be further applied to control synchronization in neural networks and synchronization realization between neural circuits. (C) 2019 Elsevier Inc. All rights reserved.