Influence of circuit capacitance on impact stress measurement of polyvinylidene fluoride sensor: A quantitative study

When the polyvinylidene fluoride (PVDF) piezoelectric sensor is used for impact stress measurement, circuit capacitance (C) is usually unavoidable and will influence the measurement results. In this study, to quantify its influence, voltage output models in charge mode and current mode are established and verified with experi-ments. On this basis, the influence of C is systematically analyzed. In current mode, the maximum output voltage (Vmax) is proportional to PVDF area A, piezoelectric constant K and loading rate F1, while the influence of C (named as P) is independent of these parameters. Shunt resistance (Rm), pulse rise time t1 and C are three interrelated parameters. When t1/RmC is large enough, P can be ignored. In charge mode, P is determined by the ratio of C to total capacitance and is independent of A, K, F1 and t1. This study is helpful to optimize the circuit design and improve the measurement accuracy.

Automated summary

This study quantifies the influence of circuit capacitance (C) on the measurement results of PVDF piezoelectric sensors. The voltage output models in charge mode and current mode are established and verified. It is found that the influence of C on the output voltage is independent of PVDF area, piezoelectric constant, and loading rate in current mode, while in charge mode, it is determined by the ratio of C to total capacitance.