Re: [TCML] Copper wire resistance calculation ?

["Chris Swinson" <list@xxxxxxxxxxxxxxxxxxxxxxxxx>]

----- Original Message ----- 
From: "Chris Swinson" <list@xxxxxxxxxxxxxxxxxxxxxxxxx>
To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
Sent: Wednesday, September 10, 2008 4:04 PM
Subject: Re: [TCML] Copper wire resistance calculation ?


> ----- Original Message ----- 
> From: "jimlux" <jimlux@xxxxxxxxxxxxx>
> To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
> Sent: Wednesday, September 10, 2008 2:36 PM
> Subject: Re: [TCML] Copper wire resistance calculation ?
>
>
> > Chris Swinson wrote:
> > > I am trying to calculate from lengh, dia, in inches to resistance.
> > >
> > > I have
> > >
> > > Rho = 0.0000000174 / 39.3700787 ( resistance per inch)
> > >
> > > (4*WL*Rho)  /  (Math.sqrt(WD)*PI)
> > >
> > > WL=wire length in inches
> > > WD = Wire dia in inches.
> > >
> > > Can't seem to get it to come out with any logical results. Could just be
> > > how I set it out, or its convertion cross sectional area wrong or
> > > something ?
> >
> > Don't you want the square of the diameter, not the square root?  i.e.
> > you want length/area * rho
>
>
> Ah!
>
> Rho = 0.0000000174 / 39.3700787 // resistivity of copper is default per
> meter, convert to inches
> area = WD*WD
> RESULT = WL / area * Rho
>
> I tried this in relation to the JavaTC demo coil, that gave 27ohms, though
> my figure comes out 0.015620142575432545 ?
>
> chris


PI=3.14159265
Rho = 0.0000000174
area = PI*(WD*WD)
RESULT = (4*WL*(Rho/.0254) /area)

I think Rho was in cm and I was working in inches, seems to behave now ?


Chris







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