# Coax Inductance

Calculate the Inductance of a Coax Cable

## Coax Inductance Calculator

### Inputs

Outer Diameter
D
Inner Diameter
d
Length of Wire
L
Relative Permeability
μR

### Outputs

Inductance:

#### Introduction

A coax is a common transmission line construction and most rf cables are coax. The impedance of the coax is a relationship of the capacitance per unit length and the inductance per unit length. This tool will help you find the inductance for a given length of coax cable.

#### Coax Inductance Description

The inductance of a coax cable can be useful to know. The variables needed in calculating this inductance are center conductor diameter, distance to outer shield, and length. You might notice that the diameter of the outer shield is not required. It is assumed that this shield is sufficiently thick. This calculation is for a loop inductance where the outer shield is the return path for the center conductor.

#### Coax Inductance Model.

The inductance of the loop created with the center conductor and outer shield.

L_{coax}\approx \frac{\mu _{o}\mu _{r}}{2\pi }\cdot \ln \left ( \frac{D}{d} \right )\cdot L

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