2) AC+C

Electrochemical Impedance spectroscopy
AC circuit + Capacitor
Xc is called the capacitive reactance of the capacitor and it is inversely proportional to the frequency, and it does not depend on the voltage and current
• Electrochemical Impeda...
Electrochemical impedance spectroscopy (EIS) is a technique used to study the electrical properties of materials and systems.
In EIS, an AC voltage is applied to an electrochemical cell, and the resulting current is measured. The impedance, which is the opposition to the flow of alternating current, is then calculated from the voltage and current. By varying the frequency of the AC signal, EIS can provide information about different processes occurring at the electrode/electrolyte interface, such as charge transfer resistance, double-layer capacitance, and diffusion.
Essentially, EIS helps to characterize materials and interfaces by measuring how they resist and respond to electrical signals over a range of frequencies.