Figure 20.

Time–resistance, time–capacitance, and time–frequency curves of the resistance of the photocell and circuit elements of the bioimpedance model estimated using oscillation waveforms and DFT. The photocell was used as (a) $R_{\mathrm{X}}$ or (b) $R_{\mathrm{PX}}$. The other resistance is 0.20 kΩ; the capacitance $C_{\mathrm{PX}}$ is 3.22 nF; and the capacitance $C_{\mathrm{SX}}$ is 9.76 nF. The times of these curves correspond to the representative points of time in Figure 19b. The insets are photocell-incorporated circuits.