Re: Capacitance of a coil

To: tesla-at-pupman-dot-com
Subject: Re: Capacitance of a coil
From: Hollmike-at-aol-dot-com (by way of Terry Fritz <twf-at-verinet-dot-com>)
Date: Sun, 17 Jan 1999 15:18:04 -0700
Approved: twf-at-verinet-dot-com

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