Figure 4

(a) Hardware block diagram of the overall system, (b) current path for 4-point measurement mode, and (c) current path for 2-point measurement mode. Z_body measured impedance, Z_i input impedance of the voltmeter, R_s output impedance of the current source, R_c contact resistance, I current, V_M measured voltage, SW switch, α the size ratio of voltage to current electrode, β the size ratio of finger to wrist electrode.