Two-layered piezoelectric bender device for micro-power generator

In this study, we investigated the possibility of use of bender type piezoelectric devices. To match the external vibration frequency with the device resonant frequency, the various devices with different resonant frequency were chosen. The two-layered device consists of different thick layers, in which each layer shows different resonant frequency. The highest power was obtained under optimization of the capacitive nature of piezoelectric device which is connected to small storage capacitor and its impedance matching by selection of suitable resistive load. Under an external vibration acceleration of 0.1 G at 120 Hz, the device exhibited a peak-to-peak voltage of 2.0 V and a power of 0.5 mW in resonance mode.