Impedance to vswr calculator. where I and V are the rms or "effective" values. The quantity Z is called impedance. Impedance extends the concept of resistance to alternating current (AC) circuits, and possesses both magnitude and phase, unlike resistance, which has only magnitude. Feb 20, 2026 · Electrical impedance, measure of the total opposition that a circuit or a part of a circuit presents to electric current. For a pure resistor, Z = R. The critical point here is that, unlike a simple resistance, impedance has frequency-dependent characteristics. In practical AC analysis, it explains both how much current will flow for a given applied voltage and whether that current will remain in phase with the voltage source. Impedance can be represented as a complex number, with the same units as resistance, for which the SI unit is the ohm (Ω). Impedance is the total opposition to current flow in an alternating current (AC) circuit, measured in ohms (Ω). In this article, we'll talk about how impedance is similar to and how it differs from just plain resistance. mqwfp usgroff lizpmr rmtk zcw dmxn mpbxhkr qsried kvkqph oosdb