AC Impedance Calculator

• •Use the AC Impedance Calculator to check your hand calculations on homework or exam problems — comparing its result with your own working helps identify arithmetic errors before they propagate.
• •Use it during the early design phase to rapidly iterate on parameters and narrow down feasible configurations before committing time to detailed finite element simulations or full design packages.
• •Use it when reviewing a colleague's calculation or checking a vendor's data sheet for plausibility — a quick sanity check can prevent costly downstream errors.
• •Use it to generate reference data for a technical report or presentation without manual computation, ensuring consistent, reproducible numbers throughout the document.
• •Use it in the field when a quick estimate is needed and a full engineering software package is not available.

The AC Impedance Calculator is a precision engineering calculation tool designed for students, engineers, and technical professionals. RLC series circuit impedance, reactances, phase angle, resonant frequency, and impedance vs frequency chart All calculations are performed using established engineering formulas from the relevant scientific literature and standards. Follow the units printed beside each field. Where a unit selector is provided, the selected unit is converted internally. Results are computed in your browser without sending data to a server, which keeps your inputs private. This calculator is intended as a supplementary tool for learning and design exploration; always verify results against authoritative references for safety-critical applications.

In AC circuits, impedance Z = R + jX extends Ohm's law to reactive components. R is resistance (real part) and X is reactance (imaginary part). For a capacitor of capacitance C at angular frequency ω, the impedance is Z_C = 1/(jωC) = −j/(ωC), so the capacitive reactance is X_C = 1/(ωC) (negative, current leads voltage). For an inductor of inductance L, Z_L = jωL, so the inductive reactance is X_L = ωL (positive, voltage leads current). For a series RLC circuit, Z = R + j(ωL − 1/(ωC)), and the magnitude is |Z| = √(R² + X²), where X = ωL − 1/(ωC). The phase angle φ = atan(X/R) represents the phase difference between voltage and current. At resonance, ωL = 1/(ωC), so X = 0 and Z = R (pure resistance, minimum impedance, maximum current). Resonant frequency f_r = 1/(2π√(LC)). Q factor Q = ω_r·L/R describes how sharply tuned the circuit is — higher Q means narrower bandwidth and more selectivity. The calculator computes impedance, reactances, phase angle, resonant frequency, and Q for RLC series and parallel circuits.

• •Filter design: RC and RLC filters for audio, radio, and power supplies use impedance analysis to compute cutoff frequency and filter response.
• •Radio frequency circuit tuning: resonant LC tank circuits in radios are designed for specific frequencies using impedance calculations.
• •Power factor correction: capacitor banks compensate for inductive motor loads, computed from impedance analysis of the motor and network.
• •Audio crossover design: speaker crossovers use inductors and capacitors to split audio signal between woofers and tweeters at specific frequencies.
• •Electromagnetic compatibility (EMC) analysis: impedance of filter networks at various frequencies determines noise suppression effectiveness.