Fig. 4From: Epidermal Differential Impedance Sensor for Conformal Skin Hydration MonitoringTypical responses of epidermal hydration sensors to changes in skin hydration at frequencies from 15 to 90 kHz. Frequency dependent impedance a amplitude and b phase of channel 4 at various hydration levels. Hydration level dependent impedance c amplitude and d phase at selected measurement frequenciesBack to article page