Alternating Current
Series RLC Impedance Calculator
Series RLC Impedance helps you find impedance magnitude from resistance, frequency, inductance, and capacitance. The page keeps the arithmetic visible so you can check the result against the original measurements.
Calculate Impedance magnitude
Replace the examples with values from the same case.
How the result is calculated
Start with the equation |Z| = √(R² + (XL − XC)²). Only Resistance, Frequency, Inductance, and Capacitance enter the numerical result.
The initial scenario returns 68.00 Ω. Re-enter field data before using the answer in a design or comparison.
Calculate series RLC impedance. For the companion impedance magnitude calculation, open Parallel RLC Impedance Calculator.
A second scenario
Change Resistance from 50 Ω to 60 Ω as the sole changed variable. The two results are 68.00 Ω to 75.66 Ω.
Keep both cases when the changed input represents genuine uncertainty.
Values this page needs
Keep distorted-waveform measurements separate from sine-wave assumptions. A source note beside each entry makes the result reproducible.
Values used below a division bar must stay positive. Convert units once, retain the original reading, and verify the converted magnitude. Continue with Motor Capacitor Calculator to evaluate required capacitance.
- Resistance
- Default example: 50 Ω. Enter resistance in Ω.
- Frequency
- Default example: 1000 Hz. Enter frequency in Hz.
- Inductance
- Default example: 0.02 H. Enter inductance in H.
- Capacitance
- Default example: 2 µF. Enter capacitance in µF.
Input quality checks
Mixing nominal and measured data is a common source of error.
Verify sign, scale, and physical meaning before accepting the number.
Applying the result
Read Impedance magnitude as the outcome of this equation, not as automatic equipment approval. Compare it with impedance, phase, waveform, and equipment ratings.
Label alternate cases rather than overwriting the baseline. If you also need impedance magnitude, continue with Series RC Impedance Calculator.
What the formula leaves out
Component losses and parasitic effects become important at high frequency.
Additional checks may be needed for frequency-dependent loss, parasitics, and waveform distortion. Document which effects were checked elsewhere in the analysis.
Use RMS values unless an input explicitly requests peak amplitude.
Common questions before using the result
What happens when a denominator is zero?
A zero denominator is undefined, so the affected field has a positive minimum.
Should I use measured or nameplate values?
Use resistance, frequency, inductance, and capacitance from one operating condition. Use RMS values unless an input explicitly requests peak amplitude.
What is not captured by this equation?
The result follows the displayed variables. Check frequency-dependent loss, parasitics, and waveform distortion separately.
Why might measured impedance magnitude differ?
First confirm that the measurements match the equation. Then review frequency-dependent loss, parasitics, and waveform distortion.
What should remain fixed in an alternate case?
Change one uncertain entry at a time and preserve the baseline. Keep distorted-waveform measurements separate from sine-wave assumptions.
What else is required before final selection?
The calculator does not approve equipment or supply an unexplained margin. Compare against a measured RMS case at the same frequency.