In Electrochemical Impedance Spectroscopy (EIS), Randles circuits are often used. A Randles circuit is and equivalent electrical circuit, where all current passes through the solution, which acts as an Ohmic resistor Rsol.
An interactive EIS of the Randles Circuit can be downloaded together with the free Wolfram Alpha Player here.
For more information, see Chapter Bode and Nyquist Plot.
In this chapter the two main ways of visualizing Electrochemical Impedance Spectra (EIS), the Nyquist and Bode plot, are presented and it is explained how different EIS of easy electronic circuits will be plotted in the Bode and Nyquist plot. This demonstrates the advantages and disadvantages of the two plots as well as serving as a foundation to understand the analysis of EIS by utilizing equivalent circuits.