Cable Impedance Calculator
Characteristic impedance of a coaxial cable from conductor diameters and dielectric constant.
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Characteristic impedance of a coaxial cable from conductor diameters and dielectric constant.
Cable Impedance Estimator
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How It Works
Key concepts behind this calculator
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Cable Quick Guide
Typical values for reference.
| D mm | d mm | er | Z0 ohm |
|---|---|---|---|
| 3 | 0.5 | 2.25 | 71.6 ohm |
| 4.7 | 0.9 | 2.25 | 66.0 ohm |
| 7.3 | 1.02 | 2.25 | 78.6 ohm |
| 2.95 | 0.46 | 1.4 | 94.1 ohm |
| Rule of Thumb | Check inputs | Use as a guide | Round sensibly |
Cable Impedance Calculator FAQ
Answers to common questions about this calculator.
The impedance a cable presents to a signal travelling along it.
They are standards for power handling and low loss.
Z0 = 138 / sqrt(er) x log10(D / d).
It is an estimate based on the inputs you enter. Check real quotes, labels or official guidance for important decisions.