Re: Calculating resistance (erratum)

[David Bowman <dbowman@TIGER.GEORGETOWNCOLLEGE.EDU>]

Oops! It seems I made a slight typo in my formulae for the equal
radius case.  I had written:

> In the special case that both cylinders have the same radius a (= b)
> the result for the capacitance per unit length boils down to:
>
> C' = [pi]*[epsilon_0]/arccosh(L/a)
>
> and the formula for the resistance between two *equal size* conducting
> dots on an infinite (otherwise uniform) resistive sheet boils down to
>
> R = [rho]*arccosh(L/a)/([pi]*d) .

But what I meant to write for these formulae were:

C' = [pi]*[epsilon_0]/arccosh(L/(2*a)) and

R = [rho]*arccosh(L/(2*a))/([pi]*d) .

In this equal radius case the argument of the inverse hyperbolic
cosine function is essentially the ratio of the distance between
the centers of the circles/cylinders to their diameter--*not*
their radius.

David Bowman
David_Bowman@georgetowncollege.edu