connect 2 different wire gauge to pos and neg speaker terminal

Kijanki wrote,

Drift velocity is average electron velocity since it is "net" axial velocity in one direction while electrons move in different directions.

https://en.wikipedia.org/wiki/Drift_velocity

Fermi velocity (random) applies only to materials when no current is applied. As I stated previously the very low Drift Velocity indicates that electrons do not (rpt not) travel rapidly at any time in the conductor. If they did the net velocity or average velocity whatever would be much higher than the centimeter per hour velocity observed.

Pop quiz, if electrons are changing direction with alternating current, why is there a net velocity in one direction along the axis? Shouldn’t there be zero net velocity? And why is the net electron velocity in one direction, not the other direction? Why do electrons favor one direction over the other, assuming vector of Drift Velocity is always in the same direction?

Geoff, re your pop quiz, as you appear to realize there is no **overall** net movement of the electrons, assuming that the DC component of the applied voltage is zero. However, within each half-cycle of the applied voltage there is net electron movement and net velocity in one direction or the other, the direction corresponding to the +/- polarity of the applied voltage at that instant. I had said that in one of my early posts in this thread.

Also, I believe that your statement that "Fermi velocity (random) applies only to materials when no current is applied" is incorrect, and that there is always random movement of some electrons, at Fermi velocity and in random directions. That is why the word "net" comes into play. Since the movements at Fermi velocity are in random directions, that velocity does not factor into (or average into) the drift velocity.

Regards,
-- Al

Therefore in this wire the electrons are flowing at the rate of 23 µm/s. At 60 Hz alternating current, this means that within half a cycle the electrons drift less than 0.2 μm. In other words, electrons flowing across the contact point in a switch will never actually leave the switch.

You’re talking AGAIN about electrons. Electric current moves with the speed of electric charge (electric field) and not the speed of electrons or drift velocity. When you flip a switch electric charge moves thru conductor at the speed of light (remember stacked balls?) magnetic wave follows at the same speed. If electric current moves at the drift velocity then in very long cable electrons at the end would not even move since it would take hours or days for charge to get there. All electrons along the wire move together instantly like stacked balls. Electric and magnetic fields have to move with the same speed (electro-magnetic field) because one doesn’t exist without the other. Again, imagine pipe filed with ping-pong balls. When you push them at one side of the pipe they will start coming out at the other instantly. When there is no change (DC) electrons move at drift velocity. DC current is proportional to drift velocity while drift velocity is proportional to magnitude of electric field. Any sudden change at the one end of the wire will travel thru the wire at the speed of light and it will arrive almost instantly and not a few days later. It will travel as wave of electric charge inside of the wire (stacked balls) and wave of magnetic field outside of the wire at the same light speed (or close to it).

Kijanki, I of course agree with your post. I suspect, though, that Geoff intended his "Exhibit A" post to be a rebuttal (mainly in its second paragraph) of the second paragraph of my post which immediately preceded it. To recapitulate the relevant paragraphs:

Almarg 9-3-2017
Also, I believe that your [Geoff’s] statement that "Fermi velocity (random) applies only to materials when no current is applied" is incorrect, and that there is always random movement of some electrons, at Fermi velocity and in random directions. That is why the word "net" comes into play. Since the movements at Fermi velocity are in random directions, that velocity does not factor into (or average into) the drift velocity.

Geoffkait 9-3-2017 (quoting Wikipedia)
By comparison, the Fermi flow velocity of these electrons (which, at room temperature, can be thought of as their approximate velocity in the absence of electric current) is around 1570 km/s.

My response to that, assuming it was intended as a rebuttal of my statement: The quoted Wikipedia paragraph, referring to Fermi "velocity in the absence of electric current," says nothing about whether or not random movement of electrons at Fermi velocity occurs when a current is present. And I believe that such movement does in fact occur when a current is present, which is why drift velocity corresponds to **net** electron movement, past any given point.

Regards,
-- Al