Fig. 6From: Design of Bionic Cochlear Basilar Membrane Acoustic Sensor for Frequency Selectivity Based on Film Triboelectric NanogeneratorThe diagram of the working principle of the sensor. a Rest state, in which the PTFE is not charged, without sound stimulation. b Contact state, in which the upper PTFE membrane is negatively charged, under sound pressure. c Separate state, in which the upper and lower PTFE membrane separate from each other, the potential difference drives free electrons to flow from the ground to silver electrode through the external circuitBack to article page