The sum of resistance, inductive reactance, and capacitive reactance in a circuit is known as what?

The sum of resistance, inductive reactance, and capacitive reactance in a circuit is known as impedance. Impedance is a comprehensive measure that quantifies the total opposition a circuit presents to alternating current (AC). It encompasses not just the resistance to current flow (resistance) but also the effects of inductors and capacitors, which store energy temporarily in magnetic and electric fields, respectively.

In AC circuits, resistance refers only to the opposition to current flow without considering energy storage elements, whereas reactance is specifically concerned with the opposition due to inductors and capacitors at a specific frequency. Impedance combines these aspects into a single value, usually represented in ohms, and is critical for understanding how circuits behave in AC applications. This concept is essential for designing and analyzing circuits in electrical engineering, especially when dealing with alternating current systems.