On Tue, 02 Sep 2008 06:18:51 -0500, flipper wrote:

On Tue, 2 Sep 2008 15:03:08 +1000, "Phil Allison"
wrote:


** The point here is about "characteristic impedance" !!

You know the definition.

Its the load R that makes a length of cable look perfectly resistive from
the feed end.

The blue lines on that graph are perfectly correct.


Then why didn't you answer his question "How could a toaster work if
its line cord has hundreds of ohms of impedance?"

The answer is because it isn't a transmission line... and neither is a
domestic speaker cable regardless of how 'fancy' you make it.

At audio frequencies transmission line effects don't begin until you
reach one or two thousand feet and at 50/60Hz power line frequencies
it's on the order of 5 miles.

In short, it doesn't make a whit of difference what their cable's
'characteristic impedance' is.


Exactly. The function of the carbon-filled plastic is to efficiently
separate morons from money.

John