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AR15.COM
9/28/2008 7:49:32 AM EDT
Been watching those science shows too much.

If like charges repel each other, how come electrons flow down a wire as electricity? Wouldn't all the electrons in the current try to repel each other and not flow?

Where do they all go once they hit ground? And where does all those electrons go to inside a CRT tube after they hit the tube on the inside?  Seems like after a while the whole inside of the tube would be clogged with electrons and have to be dumped out
9/28/2008 7:55:04 AM EDT
[#1]
Thinking of electrons like grains of sand and CRt as a box is not really correct.

on a atomic/subatomic level there is vast amount of empty space compared to matter or matterish stuff
9/28/2008 7:58:53 AM EDT
[#2]

Quoted:
on a atomic/subatomic level there is vast amount of empty space compared to matter or matterish stuff


Which is why someday I will be able to walk through a brick wall . . . I just need to line up the spaces!
9/28/2008 8:05:35 AM EDT
[#3]

Quoted:
And where does all those electrons go to inside a CRT tube after they hit the tube on the inside?  Seems like after a while the whole inside of the tube would be clogged with electrons and have to be dumped out


On the bottom there's a drainhole with an allen bolt in it.   It's called the PEBKAC.  Doesn't need to be done very often.  In fact, many people replace their monitors before it needs to be done which is why you probably didn't know that.

Make sure to wear oven mitts if you do it.



9/28/2008 8:07:52 AM EDT
[#4]
They flow because there a positive charge on the other end of the wire.  
9/28/2008 8:14:07 AM EDT
[#5]
Some of the transition metals (gold, silver, copper, i.e. the good conductors) have free electrons. You apply electromotive force and they detach from one atom and get grabbed by the next in a flow. There's really no net change; they just kind of "move down the line" due to the force. If there was a change, i.e. electrons were lost, then wires would eventually wear out.

Case in point: incandescent lightbulbs. Essentially you get the filament hot enough to "boil off" the electrons and emit photons as energy, but eventually the filament gives up the ghost.
9/28/2008 8:16:35 AM EDT
[#6]
The CRT has an anode connection (under the rubber cap on the glass) and a cathode connection on the neck of the tube.  There is a complete electrical circuit.  The electrons do go to ground.  There is no problem here.

Electrons only jump from one molecule of the conductor in response to the field charge. They just get bumped down the line.


CJ
9/28/2008 8:18:49 AM EDT
[#7]
It has to be a complete circuit for electrons to flow, no circuit, no flow, so they cant build up on anything and they cant fall out on the ground, but the ground can complete the circuit so the electrons would flow from the power source to the ground, or from the ground to the power source depending on which electrical theory you believe.
9/28/2008 8:49:42 AM EDT
[#8]

Quoted:
If like charges repel each other, how come electrons flow down a wire as electricity? Wouldn't all the electrons in the current try to repel each other and not flow?

The individual electrons repel each other but all of them are affected by the voltage gradient imposed on the wire and drift in the direction dictated by the potential gradient.


Where do they all go once they hit ground?

By reaching ground, they have returned from whence they came.


And where does all those electrons go to inside a CRT tube after they hit the tube on the inside?  Seems like after a while the whole inside of the tube would be clogged with electrons and have to be dumped out

Ha ha, very funny.

Most of the electrons are collected on a metallic wire grid or mask inside the tube and are conducted back to ground.  

During initial start up, there is some charging of the glass CRT screen.  This charging, by the uncollected electrons, continues until the glass reaches beam potential and repels any further electron impingement (20 kV for a 20 keV beam) or a potential high enough to conduct the residual beam current to ground (it is possible to make glass slightly conductive, that is, dissipative).  

This static charge is what attracts dust making your screen a dust magnet.  You can feel the static charge if your hand is near the screen.




I don't know, does that answer your question?