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Re: Capacitance of a coil
In a message dated 1/17/99 3:46:55 AM Mountain Standard Time, tesla-at-pupman-dot-com
writes:
>
> Mike,
>
> The winding length of the coil is not a parameter in this equation??
> When I use Medhurst's formula on my 10" coil, I come very close (15.88
> pF) to the measured value (based on reverse calculating from Ls and Fo).
> However, if I use the above formula, I only get 3.88 pF. Is there an
> error in the algebraic representation above?
>
> BTW, is the book Pender and Delmar's, "Electrical Engineers' Handbook :
> Electric Communication and Electronics"? I've got volume IV (Power) but
> not volume V. Is volume V worth getting, and how does it compare with
> Terman's Radio Engineers Handbook?
>
> -- Bert --
>
Bert,
I missed one thing about this. It says the winding length is about equal to
the diameter. Other than that, There is one other possibility that I
mistyped it(like I said, I never tried this equation). Perhaps it is
pi*D/(3/6*ACOSH(s)/d)). I believe the first post is correct though, due to
it's statement about the ratio of the pitch to the wire diam. being important.
I guess I will have to look at this more closely to see why it gave you such
an error.
The book I have is the third edition of the EE Handbook. The only
difference is the the editors were Pender and McIlwain, (not Delmar). I like
the book. It was given to me. Actually, the fellow who gave it to me was
wanting the volume IV (power). Do you know where I could get a copy of it
for him?
Thanks,
Mike