How is a TENG represented in an equivalent circuit model?

A Triboelectric Nanogenerator (TENG) is represented in an equivalent circuit model as either a voltage source in series with an internal impedance or a current source in parallel with an internal impedance. The voltage source model is often used for open-circuit conditions, while the current source model is used for short-circuit conditions. The internal impedance typically includes a capacitance and a resistance. The capacitance component (C) arises from the inherent capacitance between the electrodes and the triboelectric layers, and its value changes with the distance between the triboelectric surfaces. The resistance component (R) represents the internal resistance of the TENG, including the contact resistance between the triboelectric materials and the electrodes, as well as the resistance of the electrodes themselves. The voltage or current source represents the generated voltage or current due to the triboelectric effect and electrostatic induction. The values of these components (voltage/current source, capacitance, and resistance) are dynamic and depend on factors such as the frequency of operation, the materials used, and the device geometry. The equivalent circuit allows for analyzing the TENG's performance under different load conditions and optimizing its design for specific applications. For example, a TENG with high internal resistance may require impedance matching techniques to efficiently transfer power to a load.