directional cables?

Hi guys,

I think that in both this thread and the "speaker cable life span" thread a lot of the disagreement may be resulting from differing interpretations of the words "drift" and "flow."

If ac is applied to a cable, a given electron will "move" (aka "drift") an EXTREMELY small but non-zero distance during the first half-cycle of the waveform. During the second half-cycle of the waveform, it will move back to where it started. That movement will repeat for as long as the same signal is present.

On average, electrons at all points along a given conductor of the cable will do the same thing. The movement of electrons near the destination end of the cable will lag the movement of electrons near the driven end of the cable by a miniscule amount of time corresponding to the signal propagation velocity, which will be in the rough vicinity of 50 to 90% of the speed of light in a vacuum.

Although the individual electrons are moving back and forth across an infinitesimal distance, if we define a cross-section of the cable at any given point, and if ON AN RMS-AVERAGED BASIS, 6.241 x 10exp18 electrons move past that cross section in each second (in either direction), then 1 ampere of ac current is "flowing."

Meanwhile "charge" is conducted from one end of the cable to the other at near light speed, as I indicated. The charge is carried at the destination end of the cable by electrons that are not the same electrons as the ones near the source end of the cable, but which move similarly.

Agreed?

Best regards,
-- Al

Al - agreed. I objected only to term "Flow of electrons" since it has nothing to do with fast flow of charge. I stated also that with AC electrons are standing practically still - hardly a "flow of electrons". We can say that electricity (electrons) moves very slow but electric current (charge) moves very fast.

Almarg

Agreed?

Works for me.

Mr. Simple, here is a simple example.

Water does actually flow i.e. a molecule of water that enters one end of a hose flows down the length of the hose and out the other end. The water molecules in your house started out at the water treatment plant and eventually made it to your home after being pumped into pipes.

Compare that to a power plant that delivers electricity to your home. The power plant is not forcing electrons onto the power grid that then travel many miles to your house. First they step up the voltage to a very high level to increase efficiency and this high voltage electromagnetic wave travels down the wires toward your house. Somewhere close to your house is a transformer that steps the voltage down to a safer level to power your computer. The electrons that were at the power plant are not now flowing through the computer monitor you are reading this on. The energy that the power plant converted from mechanical to electrical with a generator does make it to your house, but it was not carried along by a stream of flowing electrons like the water that flows into your home.

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