 Electrical impedance spectroscopy, EIS, is a powerful technique for investigating the electrical properties of various materials. It involves applying a sinusoidal voltage or current to the material under test and measuring its impedance over a specified frequency range. The resulting impedance spectrum can be used to characterize the material's properties and behavior, making it useful in a wide range of applications including solid, liquid, semi-liquid, organic, and inorganic materials. This article was authored by M. Grossi and B. Rico.