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🔌 Impedance Calculator

Calculate impedance, inductive reactance, and capacitive reactance for AC circuits. Analyze the behavior of resistors, inductors, and capacitors in alternating current circuits.

Input Parameters

AC Circuit Impedance
Z = √(R² + (X_L - X_C)²)
X_L = 2πfL (Inductive Reactance)
X_C = 1/(2πfC) (Capacitive Reactance)

Or Enter Reactances Directly:

Results & Analysis

Enter values and click Calculate to see results

About AC Circuit Impedance

Impedance is the total opposition to current flow in an AC circuit, combining resistance and reactance. Unlike DC circuits that only have resistance, AC circuits must account for the phase relationships between voltage and current.

Key Concepts:

  • Inductive Reactance (X_L): Opposition to current change by inductors, increases with frequency
  • Capacitive Reactance (X_C): Opposition to voltage change by capacitors, decreases with frequency
  • Impedance (Z): Vector sum of resistance and net reactance
  • Resonance: Occurs when X_L = X_C, minimizing impedance

HOW TO USE

Enter the resistance (R), inductance (L), and/or capacitance (C) values along with frequency. Click Calculate to find total impedance, phase angle, and resonant frequency.

FORMULA USED

Z = √(R² + (XL - XC)²)
XL = 2πfL
XC = 1÷(2πfC)
Phase angle θ = arctan((XL - XC) ÷ R)

WORKED EXAMPLE

R=100Ω, L=0.1H, C=10μF at f=50Hz: XL = 31.4Ω, XC = 318.3Ω, Z = √(100² + (31.4-318.3)²) = 303.3 Ω.

FREQUENTLY ASKED QUESTIONS

Q: What is impedance?

A: Impedance (Z) is the total opposition to AC current flow, combining resistance (R) and reactance (X): Z = R + jX.

Q: What is inductive reactance?

A: XL = 2πfL. It increases with frequency — inductors oppose high-frequency AC more than low-frequency.

Q: What is capacitive reactance?

A: XC = 1/(2πfC). It decreases with frequency — capacitors pass high-frequency AC more easily.

Q: What is resonance in an RLC circuit?

A: Resonance occurs when XL = XC. Resonant frequency fr = 1÷(2π√(LC)). Impedance is minimum at resonance.