Load-resistance-dependent charge reduction in a droplet-based electricity generator revealed by synchronized charge analysis and high-speed imaging

The physical origin of load-resistance-dependent charge extraction in droplet-based electricity generators (DEGs) remains unclear. In this study, synchronized electrical measurements and high-speed imaging were used to investigate charge reduction, peak delay, and polarity reversal in a DEG. The positive transferred charge decreased under high-load-resistance conditions despite prolonged discharge duration. Comparison between current waveforms and droplet deformation revealed that droplet shrinkage accounted for 92% and 94% of the observed charge reduction at 10 and 16 MΩ, respectively. An extended biased-capacitor model reproduced the major experimental trends, providing a unified interpretation of charge reduction, peak delay, and polarity reversal.