Recent progress in perovskite solar cell (PSC) research has hope for the adoption of solar energy. To gain a deeper understanding of the underlying mechanisms is crucial to advancing current solar technologies. Impedance spectroscopy (IS) is a key method for exploring the internal dynamics of solar cells. Ongoing analysis and optimization of electrochemical spectroscopy data have revealed complex operational insights. This section collects the physical principles driving PSC expansion, supplying a complete resource on resistance plots, corresponding circuits, and allied procedures.