mass of an electron is ‎9.10938356 ×10−31 kg

OK almost massless, unfamiliar with electron drift concept? must be with 0V potential? will look it up...

 

Sorry Sam, but you misunderstand how electricity travels.

He's mixing the physics meaning of 'electricity' and electrical energy. Two separate things with different physical processes.

http://amasci.com/miscon/maxwell.html

 

OK that blew my mind.... "electrons flowing across the contact point in a switch will never actually leave the switch"

The fermi velocity is what I know of.

 

Sorry Sam, but you misunderstand how electricity travels.

That was my first impression as well...

 

OK that blew my mind.... "electrons flowing across the contact point in a switch will never actually leave the switch"

The fermi velocity is what I know of.

The fermi velocity of copper electrons is indeed very fast but it is totally random so the net speed is zero. The electron drift velocity is the slight bias in the random movement that is very slow.
http://webcache.googleusercontent.c...+&cd=1&hl=en&ct=clnk&gl=us&client=iceweasel-a
h

 

So If I flip the switch in the house for the lights in the remote garage 30 meters from the switch in the house it takes 3,000 seconds to reach the bulb and another 3,000 seconds to return to ground before the light comes on?

When you open your kitchen faucet, water comes out immediately. But the transit time from the aquifer, though your well pump, water tank, water softener, piping, etc. might take hours. So what? The energy arrives immediately.

 

Yes I kinda remember that from long ago. Push an electron in one end of a long wire and an electron must pop out the other end to make room for it was the gist of it. Thanks for reminding me and the link. It was a good read.

 

mass of an electron is ‎9.10938356 ×10−31 kg

OK almost massless, unfamiliar with electron drift concept? must be with 0V potential? will look it up...

When dealing with relativistic velocities, things that are almost massless become very massive indeed. Think of this, the Large Hadron Collider has a 27 km circumference, and that's because it needs to accelerate electrons to a velocity slightly larger than what the 3.2 km long linear particle accelerator at Sandford is able to. And unlike Standford's machine, the LHC circles the electrons many times around before smashing them against a target.

 

I think the LHC primarily accelerates protons but it can also handle heavy ions.

13 TeV head on collision energy gives about 7500 equivalent times the rest mass of each proton.

 

I think the LHC primarily accelerates protons

... nuisance...

 

This water analogy fails to capture the essential nature of a circuit, that it's a closed loop. Water flow from a faucet is more one-way. I suppose you could think of water leaving the faucet to be analogous to electrons hitting ground potential.

Actually water flows back into environment, in turn heading towards the seas, then is evaporated back into atmosphere,
winding up as rain back into aquifer, very much a closed loop system.

And each and every water molecule always find their way back to origin, just like salmon returning from the sea.........


Regards, Dana.

 

And each and every water molecule always find their way back to origin, just like salmon returning from the sea.........

Another poor analogy. All Pacific salmon and most Atlantic salmon die after spawning. They never repeat the cycle.

 

Another poor analogy. All Pacific salmon and most Atlantic salmon die after spawning. They never repeat the cycle.

 

Another poor analogy. All Pacific salmon and most Atlantic salmon die after spawning. They never repeat the cycle.

Thats what happens when one thinks only their world matters. I am an Atlantic resident. But overall, even though Atlantic
can spawn multiple cycles, majority only good for one or two. But then statement that they return from sea, east or west,
pretty much true for one cycle, sans effects of predation. One cycle complete.


Regards, Dana.

 

He's mixing the physics meaning of 'electricity' and electrical energy. Two separate things with different physical processes.

http://amasci.com/miscon/maxwell.html

Ah, my friend Bill’s website. It’s nice to see him cited. When we worked together at the Boston Museum of Science, he built a nice exhibit that showed the speed of electron flow though a circuit using chasing LEDs. This was in the 80s, a long time ago. It was a nice demo and I‘ve seen it replicated several times since.

Bill’s great, and his site is a treasure trove of the good and the weird.

 

... nuisance...

It is, after all, a hadron collider, not a lepton collider.

 

Electron movement example: The Newton Cradle. You only need to watch the first minute. But the rest of it is pretty interesting as well. Can represent many different things regarding electron movement and electric pressures.

By the way - the mass of a proton plus an electron is equal to the mass of a neutron. Interesting.

 

Wow!!! I NEVER expected such an absolutely amazing discussion to crop up around this thread. I was hesitant to even post it, because I thought it would get a, "Go read a book you dummy!" response, or no response at all. I deeply appreciate you guys not giving me the "Go do your homework," response, because the questions that I have about electronics, physics, electricity, circuits, et cetera, never seem to be clearly addressed in any of the books I've bought or read. Just like with most disciplines books written for beginners tend to give very weak flawed analogies that under explain concepts, and then there is this huge jump to more intermediate books that assume you fully understand 2 years of physics.
Here are three concepts that come to mind right off hand that I have never been able to find a really concrete deeply connective explanation for.

• Electron flow direction: Electrons flow from negative terminals to positive terminals, or Positive to negative? Why? And why draw it backwards most of the time... but not all of the time?
• Grounding: In my original post, I said that if I took a copper wire that is connected to just one terminal of a 9V battery, and put it in my mouth, I would not feel that weird tingle that you get when you do the same with wires touching both terminals completing the circuit across your tongue. And I made the assumption based on that scenario, that I could take a wire that is hooked to only one terminal of a 600V power source, and put it in my mouth as well, as long as I don't touch the other terminal of that power source. A few people massively corrected me on that (I'd never try anything like that btw), saying that I'd be "grounded" and I'd die. I don't understand that principle at all. Same with why we solder a wire to the chassis of an amplifier to "ground it."
• Electron movement under AC Current: With DC current, electrons flow in one direction. With AC current, do the actual electrons move x-number of µm, and then those same exact electrons are pulled back to where they started (0) and then pulled x-number of µm in the other direction... essentially never moving on down along a wire, but just kind of being pushed and pulled back and forth? As far as I know, there is no "water analogy" to explain alternating current.

 

Hello D007,

Sorry about your thread being hijacked in so many directions but it makes for entertaining reading and discussion, besides academic clarification. That's what AAC forums are all about.

Electron flow direction
This is just convention. Electricity is the flow of charge. The charge of an electron is considered to be negative by convention. Negative charge flow in one direction is equivalent to positive charge flow in the reverse direction, i.e. the two negative signs cancel. In solid-state electronics there is the useful concept of electron and hole movement.

Sometime in recent history someone attempted to be scientifically correct by changing all prior concepts of electricity flow when they decided that the electron is negatively charged. It is all convention. Which end of a bar magnet is north or south? Is Australia really the land down under?

Stick to one convention, either positive charge flow or negative charge flow. Electronic symbols are based on positive charge flow. If you always want to reverse things in your head, go ahead, that is fine by me.

Grounding
Ground means different things to different people. We can elaborate on that later. For charge to flow you need a circuit for the most part (there are special cases where this does not apply). For current to flow from a battery you need to complete that loop around the circuit. Ground simply means that we will call a given point (node) in the circuit our starting point for measuring voltages. It becomes or 0V reference point, very much as how we call sea level our 0-altitude reference point.

Electron movement under AC Current
You are correct. With a DC voltage applied, all free electrons drift very slowly around the loop. What happens very quickly is their response time to the voltage pressure. In a piece of copper wire, the wave travels at about 70% of the speed of light whereas the cloud of electrons drift relatively slowly.

In AC current, the voltage pressure goes positive and negative and so do the electrons. It is not necessarily the same electrons that move. Electrons are more like a cloud of starlings or shoal of minnows. Each minnow does not behave the same way. The movement of each individual is almost random based on probability theory. The net drift is zero in AC. (AC also means different things to different people and that is another lesson.)

 

Electron flow direction: Electrons flow from negative terminals to positive terminals, or Positive to negative? Why? And why draw it backwards most of the time... but not all of the time?

Benjamin Franklin is the one who described current as flowing from positive to negative. It was based purely 50/50 possibility of being right. He took the educated position that positive meant more and negative meant less. Hence, current flow is what is standard and the way it's drawn. However, electron flow, which didn't come to be understood for some time, actually represents what's happening on an atomic scale. The Proton is too large and heavy to move whereas the electron is freely liberated (in certain materials). This is why copper is a favorite conductor. Gold is better but much more expensive.

Consider a battery: It has a positive end and a negative end. At the positive end there is an absence of electrons - and they want to go home. When provided a pathway to home they will go. That's electron flow, from negative to positive. That's the best I can do to explain it. There's probably more to it than that.

Best to get comfortable with conventional current flow as described by Ben Franklin. Just about the entire industry works from that standpoint. So be like a lemming and follow the crowd.