[SI-LIST] Re: Inductance of wire section
- From: Kim Flint <si@xxxxxxxxxxxx>
- To: si-list@xxxxxxxxxxxxx
- Date: Fri, 05 Sep 2003 12:35:38 -0700
Hi-
I'm curious about assumptions made in some of these inductance formulas. I
understand inductance as requiring a coil of wire, wherein magnetic flux
would intersect the area of the coil. "Inductance of a wire segment"
doesn't really mean anything without understanding where the rest of the
current path forming our coil is located. So I'm guessing these formulas
are approximations based on some set of assumed conditions, like height
above ground or something like that? Does anybody know what those
assumptions are in this case? I'd like to understand where I can expect
this formula to be reasonably valid.
thanks!
kim
At 08:57 AM 9/5/2003, Stuart Brorson wrote:
>Hi Guys --
>
>Thanks for all your answers. I used the following formula from Bart:
>
>L = K * length * [ ln(4*length/Diam) - 0.75 ]
>
>L = Inductance in nanohenries
>D = Diameter of wire in cm
>length = Length of wire in cm
>K = 2
>
>stuck it into Gnumeric (Linux-based Excel replacement), and got the
>following answers:
>
> Unit qnty qnty qnty
>K 2 2 2
>Length cm 1 1 1
>Diam cm 0.08 0.06 0.04
>
>Inductance nH 6.324 6.899 7.710
>
>depending upon the wire diameter. Using the below figure of 20nH/in,
>and knowing that 1in = 2.54cm, I get L = 7.87 nH.
>
>Therefore, I think we have nailed it: L = 7nH/cm +/- 10% or so.
>
>Thanks again for all the answers!
>
>Stuart
>
> >
> > Hi Stuart: The ROT I use is 20nH/in.
> > BTW, I verifed this using a 2D extractor
> > and increasing the boundary distance far
> > away from the wire to minimize mutual indutance.
> >
> >
> > Hope this helps
> >
>------------------------------------------------------------------
>To unsubscribe from si-list:
>si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
>
>or to administer your membership from a web page, go to:
>//www.freelists.org/webpage/si-list
>
>For help:
>si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
>
>List archives are viewable at:
> //www.freelists.org/archives/si-list
>or at our remote archives:
> http://groups.yahoo.com/group/si-list/messages
>Old (prior to June 6, 2001) list archives are viewable at:
> http://www.qsl.net/wb6tpu
>
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
or to administer your membership from a web page, go to:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List archives are viewable at:
//www.freelists.org/archives/si-list
or at our remote archives:
http://groups.yahoo.com/group/si-list/messages
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu
Other related posts:
