What is the term used for the total opposition to AC, combining resistance and reactance?

The term used for the total opposition to alternating current (AC), which combines both resistance and reactance, is impedance. Impedance is a comprehensive measure that quantifies how much a circuit resists the flow of AC. It encompasses not only the resistance, which is the opposition due to the material properties and physical dimensions of the conductor, but also reactance, which arises from reactive components such as inductors and capacitors.

Inductive and capacitive reactance are frequency-dependent components of impedance. This means that as the frequency of the AC changes, the reactance will also change, thereby affecting the total impedance. Therefore, when analyzing circuits in AC, understanding impedance is crucial for accurately calculating how much current will flow for a given voltage.