text: Plotting the Nyquist diagram with a potentiostat and an impedance analyzer, most often included in modern potentiostats, allows the user to determine charge transfer resistance, double-layer capacitance and ohmic resistance. The exchange current density  can be easily determined measuring the impedance of a redox reaction for .
  Nyquist diagrams are made of several arcs for reactions more complex than redox reactions and with mass-transfer limitations.