# Length of wire in a coil of known dimensions?

1. May 25, 2012

### carmatic

suppose that i have a wire with a known thickness ... and i want to wind it around a solid cylinder with known dimensions, and in the end make a coil with the same length as the solid cylinder

how do i relate between the length of wire required and the diameter of this coil?

2. May 25, 2012

### Catahoula_Dog

W = Length of Wire
D = Diameter of Pipe
L = Length of Pipe (and wire coil)
T = Thickness of Wire
∏ = pi

W = ∏(D+T/2)(L/T)

This should give you what you need under ideal situations

The length of the wire is equal to the length of one loop of wire around the tube, ∏(D+T/2), times the number of times it is able to go around the tube, (L/T).

Be sure that your units are all the same (use some common measurement like 'cm' for all of these).

3. May 26, 2012

### carmatic

that seems to only apply for a single layer of wire coiled onto the core

in order to account for multiple layers of wire, it looks like it will take calculating a linear combination ( http://en.wikipedia.org/wiki/Linear_combination ) where you have an integer multiple of T?

Last edited: May 26, 2012