Back |
---|
(Partly from http://www.electronics-lab.com/blog/?p=18953 )
In deriving the formula for characteristic impedance resistance per unit length can be neglected. The impedance can be found from the values of capacitance per unit length (C/h) and the inductance per unit length (L/h):
![](https://www.verulam-arc.org.uk/wp-content/uploads/2020/03/Coax-Calculations-1-1.png)
where D is the diameter inside diameter of the shield, d is the outside diameter of inner conductor, h is the length of the cable, and e is the dielectric constant of the insulator.
The series inductance per unit length, in Henrys per meter, is given by:
![](https://www.verulam-arc.org.uk/wp-content/uploads/2020/03/Coax-Calculations-1-2.png)
(See http://en.wikipedia.org/wiki/Impedance_of_free_space )
![](https://www.verulam-arc.org.uk/wp-content/uploads/2020/03/Coax-Calculations-1-3.png)
Back |
---|