fig3

Figure 3. Conventional disposable Ag/AgCl biopotential electrode interface and its circuit equivalent model. E_hc: Half-cell potential of electrode. C_d: capacitance of double layer in the electrode/electrolyte interface. Rd: resistance of double layer in the electrode/electrolyte interface. R_g: resistance in the electrolyte. E_se: potential drop from the ionic concentration difference between stratum corneum and electrolyte. C_e and R_e: capacitance and resistance of the epidermis impedance, respectively. R_u: resistance representing dermis layers.