ETA Electronics Certification Practice Exam

Impedance is the measure of total opposition to current flow in AC (Alternating Current) circuits. It encompasses not only the resistance found in DC (Direct Current) circuits but also the effects of reactance, which arises from inductors and capacitors. In AC circuits, the current is affected by both the resistive and reactive components, making impedance a more comprehensive measure. Resistance refers specifically to the opposition to current flow regardless of the type of current, while current itself indicates the flow of electrons and does not describe opposition. Voltage measures the potential difference that drives the current flow but does not convey any information about how much the current is hindered. Therefore, impedance is the most accurate term to describe the total opposition to current flow in alternating current scenarios.