## PSN-L Email List Message

Subject: Re: Coil winding formula ?
From: barry lotz gbl@.......
Date: Mon, 24 Jul 2000 21:17:15 -0700

```Arie
"And now for something completely different". If your question is for
determining the length of wire for a multiple turn coil , I would use the
average diameter(to get the average circumference- not considering nesting
condition ),length, and wire diameter.
let see...   looking at a cross section,
if  # of turns = (L/gage)* (b/gage) , where L=coil length and b = coil
and if total  length of the wire= (# of turns)*(d+b)*pi  , where d is the
coil ID
assuming   (b+d)*pi   is the average circumference
of a turn
then solve the first equation for b and substitute in second equation
and punt- maybe there is a simpler way
-----
I have a slightly different formula(s) for inductance (got it from that small
information pocket book available at electronic store checkout counters).
For single layer coil:
I=(R^2 * N^2)/(9*R+10*L)
For multiple layers:
I=(0.8*(R^2*N^2)/(6*R+9*L+10*B))

where:       I= inductance in microhenrys
N=number of turns
L=length of coil(inches)
Regards
Barry

Arie Verveer wrote:

> Hi, A long time ago, far, far away, I used to remember a simple formula
> that gave the length of wire for a coil, given the number of turns, internal
> diameter, length of coil and gauge of the wire. But alas, I cant remember
> it, so if anyone knows such a "winding" formula, I would be most
> appreciative. Or anything like it.
>
> Arie

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