On Fri, 12 Nov 2004 17:09:35 +0000, Paul Burridge
wrote:


Sorry, Don, you obviously haven't thought this through. Since *all*
their current is returned, I cannot have used *any* of it. Whatever
the voltage might be, multiplying it by zero Amps still gives zero
power!

---
That's not how they do it.

Since they know that they'll get back every bit of current they send
you, they keep track of what they send you for three months, normalize
it to 1 and call it "a", call what you send them back "b", and then do
the followwing maths:

normalize a:
a = 1

set b = a:
a = b

multiply both sides by a:
a² = ab

subtract b² from both sides:
a² - b² = ab - b²

factor both sides:
(a + b)(a - b) = b (a - b)

divide both sides by (a - b):
(a + b)(a - b) = b (a - b)
-------------- -----------
(a - b) (a - b)

remove terms which cancel ((a -b)) from both sides:
a + b = b

convert:
1 + 1 = 1

So, you can see that the sum of the amount they sent you and the
amount they received back _has_ to be the same as the amount they sent
you, and that's what they bill you for.

--
John Fields