Operational Amplifier-Based Memcapacitor Emulators and Their Applications

This work proposes three configurations of memcapacitor emulators based on operational amplifiers. The first two configurations utilize two operational amplifiers, three memristors, one resistor, and one capacitor. The third configuration requires two operational amplifiers, one capacitor, one memristor, and three resistors for its realization. The key innovation of the proposed circuits lies in integrating a memristor, which introduces non-linearity and memory capabilities, making it ideal for emulating memcapacitive behavior. The proposed circuits demonstrate simplified structures compared to most existing designs while achieving reliable performance across a frequency range of up to 6 kHz. The LTspice tool has been utilized to perform all simulations. The pinched hysteresis loops are plotted to validate the memcapacitive behavior, the memory-retaining property is evaluated using a non-volatile plot, and robustness is verified by performing the Monte Carlo simulations. The proposed emulators are validated utilizing both the SPICE model of the memristor and a memristor emulator circuit. Experimental results have been included to validate the key fingerprint, that is, pinched hysteresis loop of the circuit using commercially available AD711 ICs. Additionally, three applications—neural spike generation, adaptive learning circuit, and chaotic oscillator—are demonstrated, highlighting the emulator's versatility in neuromorphic computing and adaptive systems.