mooreamps wrote:jaysg wrote:I have these vague recollections about all of this:
Benjamin Franklin was the idiot who decided that the election would have negative charge.
In conductors and semiconductors, electrons don't actually flow. It's more like they wiggle and are not stripped away from their nucleus's.
Yes, they do. An electron will leave the orbit of one nucleus and travel to another. This is covered in basic radio frequency antenna theory, where we can measure the amount of current feeding a transmitting antenna.
-g
Ahem... No. Well yes and no. They do leave their orbits. In a metal and in a semi conductor, conduction electrons are delocalized. It's the so-called "plum-pudding" model in a sense. But it's not covered by RF antenna theory but solid states physics.
With any AC signals, Jay is right: the electrons do not actually move, they "wigle". They DO move when DC current is involved.
Actually, each individual electron move at a speed neighbooring the speed of light (~ 10^7 cm/s in some metals). And on average, they do so in ALL directions. But they collide with the atoms (which is responisible for the resistivity in a metal). When no voltage is applied, the electrons moves around like crazy at ~10^7 cm/s but on average "run around in circles" (they do not "move"). When you apply a current, they "run around in circles" around a center that slowly drift at the speed of the current (a few meters per seconds IIRC. I think you could walk as fast as the drift current. That drift current is the actual current that goes into ohm's law).
When an AC signal is applied, the current is half the time positive and half the time negative. So the electrons drift both ways and on average do not move. Actually, when an AC signal is applied, the wave energy does NOT travel in the wire but rather somewhere mid-air between the "live" and ground. For example, in a coax cable, the energy travel between the center wire and the shield. Now THAT is something classical electromagnetism (AKA RF antenna theory) teaches you.