Impedance Spectroscopy

A measurement-and-analysis technique that applies a small-amplitude, frequency-controlled perturbation (AC stimulus) to a circuit, device or material and records the complex impedance Z(ω) = V(ω)/I(ω) across a range of frequencies to separate and quantify resistive, capacitive, inductive, charge-transfer and diffusion-related processes and to fit equivalent-circuit or kinetic models.