“…The conversion efficiency of the PVDF transducer with the 1.66 F output super capacitor array now lies in the range between 2.7-4.2 %. These efficiency levels agree with the above approximate calculation and agree with what is usually reported in the literature [47,192,197,198]. However, the experiments are usually performed with microFarad capacitors, or resistive circuits and -as already discussed, definitions of efficiency vary between research groups [181].…”