Impedance Calculator
ac impedance calculator. Get instant, accurate results. Enter values for instant results with step-by-step formulas.
Reviewed for accuracy by Manoj Kumar, Mathematics Educator
Impedance Calculator
Calculator
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Formula: Z = √(R² + (X_L - X_C)²) | φ = arctan((X_L-X_C)/R)
Worked example — 141.4 Ω at 45°
Formula
Z = √(R² + (X_L - X_C)²) | φ = arctan((X_L-X_C)/R)
Total opposition to AC current flow. Combines resistance and reactance.
Worked Examples
Example 1: RLC circuit
Problem:R=100Ω, XL=150Ω, XC=50Ω
Solution:Z=√(10000+10000)=141.4Ω, φ=45°
Result:141.4 Ω at 45°
Frequently Asked Questions
What is AC impedance?
Impedance (Z) is the total opposition to alternating current in a circuit, combining resistance (R) and reactance (X). It is calculated as Z = √(R² + (X_L − X_C)²), where X_L = ωL is inductive reactance and X_C = 1/(ωC) is capacitive reactance. The SI unit of impedance is ohms (Ω).
How do you calculate impedance in an RLC circuit?
Use Z = √(R² + (X_L − X_C)²) and phase angle φ = arctan((X_L − X_C)/R). For R = 100 Ω, X_L = 150 Ω, X_C = 50 Ω: net reactance X = 100 Ω, Z = √(10000 + 10000) = 141.4 Ω, and φ = arctan(1) = 45°, indicating an inductive circuit.
What units does the impedance calculator use?
Resistance R, inductive reactance X_L, and capacitive reactance X_C are all entered in ohms (Ω). Reactance can also be computed as X_L = 2πfL and X_C = 1/(2πfC) before entering. Output impedance Z is in ohms, phase angle φ in degrees, and power factor PF is dimensionless (0 to 1).
What is impedance and how does it differ from resistance?
Resistance opposes DC current and is purely real. Impedance opposes AC current and includes resistance plus reactance (from capacitors and inductors). Impedance is a complex number: Z = R + jX, measured in ohms. Capacitive reactance decreases with frequency while inductive reactance increases with frequency.
Reviewed for accuracy by Manoj Kumar, Mathematics Educator · Editorial policy
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