Figure 7.

Equivalent electrical load when dielectric dispersion was included. (a) The voltage-regulated waveform applied to the stimulation electrode (top), the magnitude of the discrete Fourier transform (DFT) of x (middle), and the magnitude of the transfer function for the voltage drop across the tissue (bottom). (b) The inverse DFT yielded an equivalent waveform of the voltage drop across the tissue over time (V_a), and a fitted three-element Randles circuit was used to calculate the lumped access resistance (R_a) of the tissue. C_dl = lumped double-layer capacitance, R_f = lumped Faradaic resistance, and C_a = the lumped (access) capacitance of the tissue. C_a was ignored because it had a negligible effect on the filtered waveform.