Figure 2.

(a) The finite element analysis of a 5 × 5 mm² device under a constant stress of 30 kPa onto its working area. (b) The electrical signal of the device versus applied stress at a constant frequency of 10 Hz. (c) Voltage output of the device as a function of time under stress of 87.5 kPa. (d) The electrical signal of the device versus time at a constant stress of 64 kPa under three different frequencies. (e) Peak values of each electrical output generated by the 64 mm² device with over 4500 continuous working cycles under the load and frequency of 32.4 kPa and 10 Hz. (f) The details of the electrical signal in the marked region of (e).