Fig. 4
Calculated characteristics of the contact-separation mode TENGs. a The periodic force F. b The periodic motion of the top layer. c Transferred charges-time relationship at different R in the contact and separation process. d Current-time relationship at different R in the contact and separation process. e Voltage-time relationship at different R in the contact and separation process. f The relationships of instantaneous maximum power with resistances in the contact, separation, and the whole process