"infamis" wrote in message
om...
In article , "mc"
wrote:
Now replace that battery by an AC generator. You still need only two
wires.
The sine wave generator acts like a battery that is switching back and
forth
periodically.

OK, I understand that....

Audio equipment designates one of the two wires "ground" because that is
the
one that is shared by many different inputs and outputs. "Ground" is not
an
electrical phenomenon; it just means something has been chosen to be the
common reference point.

But if you're throwing away one of the wires from the audio signal &
replacing
it by a wire connected to the ground (the metal rod in the earth), how can
that metal rod be generating the rest of the signal. In DC, you have (+)
and
(-). It seems to me that it's like throwing away the (-) away and
replacing it
by, I don't know (X). That makes me wonder where the other half of the
signal
is coming from.

Rods in the ground have nothing to do with it. "Ground" means something
entirely different here -- it means "the conductor that happens to be shared
by the input and the output." See previous message.