Electrical impedance is a fundamental concept in electrical engineering that quantifies the total opposition a circuit presents to the flow of alternating current (AC). Unlike simple resistance, which only accounts for energy dissipation as heat, impedance is a complex measure that incorporates both resistance and reactance. Reactance, which arises from inductive and capacitive components, represents the opposition to current flow due to the build-up or discharge of electric fields and magnetic fields. Measured in ohms, impedance dictates the voltage-current relationship within an AC circuit and is crucial for analyzing the performance of components such as transformers, filters, and transmission lines, ensuring that energy transfer across circuits can be accurately modeled and optimized.