Figure 4.
(a) Scheme of the press cycle and release cycle of mechanical loading equipment, (b) the short-circuit current of PENG during pressing-releasing cycles, (c) signal analysis corresponding to the cyclic pushing–releasing process, (d) output voltages from PENG with different load resistances, (e) the variation of output voltages and calculated currents across load resistances (inset is the corresponding circuit), (f) power density across different load resistances.