impedantie

Impedantie, often denoted Z, is a measure of opposition to the flow of alternating current in an electrical circuit. In the common mathematical model, impedance is a complex quantity Z = R + jX, where R is the resistance and X is the reactance. The magnitude |Z| indicates how much the circuit attenuates a sinusoidal signal, while the phase angle φ = arg(Z) describes the shift between voltage and current. Reactance arises from energy storage elements and depends on frequency: inductive reactance X_L = ωL and capacitive reactance X_C = -1/(ωC). Therefore the impedance of a simple resistor, inductor, or capacitor is Z = R, jωL, and 1/(jωC) = -j/(ωC), respectively.

In networks, impedance combines through series and parallel rules. For components in series, Z_total = Z1 + Z2 + …; for parallel, 1/Z_total = 1/Z1 + 1/Z2 + …. Calculations generally require complex arithmetic, and the resulting impedance characterizes how voltage and current relate by V = IZ.

Applications of impedantie are widespread in electronics and signal processing. It is central to AC analysis, filter design, and impedance matching for maximum power transfer. Impedance spectroscopy uses frequency sweeps to probe material properties, while RF and audio design rely on precise impedance control to achieve desired frequency responses.

Beyond electronics, analogous concepts exist in acoustics and mechanics. Acoustic impedance defines the ratio of acoustic pressure to particle velocity, and mechanical impedance relates applied force to velocity. The term impedantie reflects these cross-domain ideas of opposition to flow and motion.