# How to calculate the inductance of a Disc coil?

#### Walks91

Joined Apr 28, 2018
20
I'm trying to figure out a way to calculate the inductance through a disc coil or bitter coil and how that inductance will affect the current going through it as well as the frequency of the current. With such a large difference between the outer and inner diameter of the coil can it be calculated the same way as a regular coil? Theoretically this would be used for a high power application. I attached a picture of the coil in question.

#### Walks91

Joined Apr 28, 2018
20
As an example if I were to use a copper coil with 10 discs (10 turns) each being 1 mm thick and a inner diameter of 4 cm and outer diameter of 10 cm. How is the inductance of this type of coil calculated?

#### BR-549

Joined Sep 22, 2013
4,938
It might have more capacitance than inductance.

#### wayneh

Joined Sep 9, 2010
16,128
Somewhere I saw a table of the inductance approximation formula given various shape factors. The typical form gives the Wheeler formula but very wide or very long coils are better approximated with variations of that formula.

#### Walks91

Joined Apr 28, 2018
20
Thank you Wayneh, I have yet to come across that table, but if you are able to share it that would be much appreciated!

#### wayneh

Joined Sep 9, 2010
16,128
Thank you Wayneh, I have yet to come across that table, but if you are able to share it that would be much appreciated!
There’s a chance I saved it. I find it hard to toss obscure references like that, especially ones that cover a ton of work. I’ll look.

#### The Electrician

Joined Oct 9, 2007
2,751