[Next][Index][Thread]
No Subject
C = R
----------------
9 X 10^9
where R is the radius in meters and C is Farads.
The capacitance is simply a function of the surface area.
I didn't have a formula for calculating the area of a toroid, so I modified
the formula for the area of a cylinder, "bent" it into a ring, and added the
area of the center disk.
I had a table of actual values for several toroids of different chords and
diameters. I then played with fudge factors in the formula until it would
yield results which matched the table to within 5%.
A friend of mine later took my crude formula and reduced it, but I never
bothered to change the original. If it ain't broke, I don't fix it.
My formula appears to work on small toroids all the way up to at least 8 to
12 inch chords and up to at least 8 foot diameters. I suspect that the error
of the formula would increase beyond these sizes. However, the largest
toroid I've built so far is only 62 inches in diameter, and I don't plan on
going much larger in diameter than that.
So, as you can see, I'm not a mathematician or a scientist. I just make it
work.
I hope this answers your question.
Bert