What is impedance?

Impedance is defined as the combined effect of resistance and reactance in an alternating current (AC) circuit. It represents how much a circuit opposes the flow of electric current, allowing for the consideration of both the resistive and reactive components.

Resistance refers to the opposition to current flow that is constant and does not vary with frequency, while reactance is frequency-dependent and encompasses both inductive and capacitive effects. By combining these two, impedance provides a comprehensive measure that is critical in AC circuit analysis, where both types of opposition play significant roles.

Understanding impedance is essential for tasks such as calculating total circuit loads, optimizing power factor, and analyzing how different components interact under AC conditions. Therefore, recognizing impedance as the combined effect of resistance and reactance highlights its importance in electrical engineering and helps clarify its practical applications.