Propeller Head Plaza

Posted by geoffkait (M) on May 03, 2022 at 09:42:31

In Reply to: RE: "How electricity flows in an AC circuit" posted by geoffkait on May 02, 2022 at 06:24:52

What makes the speaker driver work? It's the interaction of the moving electric field carried by the speaker cable interacting with the large permanent magnet attached to the driver. Already we have established that the Poynting vector can't be the signal, mainly because it doesn't alternate directions. Furthermore the units of the Poynting vector is Watts per cubic meter. Yes, Watts per cubic meter. Dear readers, does that look like a signal to you? It's the power density.

But what we have shown already is the audio waveform is the combined push and pull of the two + and - wires of each speaker cable. And what produces the electric field? That's the current, which is calculated according the number of moving electrons. So, at the end of the day electrons are really the "audio signal." The voltage produces the electric field and the current produces the magnetic field portions of the EM wave.bog course the e and m fields have vectors that are orthogonal to the direction of electron flow and to each other.

The Poynting vector is just a calculated value based on the electric and magnetic fields and points toward the speakers. But the Poynting vector doesn't produce the audio signal (waveform), the alternating current does. Just because the energy flows outside the wire does not mean the signal travels outside the wire. We have shown that the "signal" is actually the current so the "signal" does travel back and forth since it's an AC circuit. The Poynting vector is a red herring.

Edits: 05/03/22   05/03/22   05/03/22   05/03/22   05/04/22