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Can a generator run out of of electrons? Where do the electrons come from?

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GreenAce92

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Pretty sad that I am asking this when I took E&M as a physics major 3 years ago.

"When a conductive wire is in a magnetic field, current is induced"
Right hand rule, point your thumb in the direction of the current, magnetic field around wire.Or is it simply orthogonal to the wire? Anyway...

When you take rotational motion from an outside source whether a spinning turbine or up/down motion of a wave, the wires are cutting through a magnetic field... but the electrons being generated, where do they come from and can they run out?

"free electrons"

Anyway, I'd appreciate a very detailed response.

Thank you
 

There is a postulate which says that there no exists magnetic field, nor electric field, but both walk together, which means that one generate other and vice-versa. I admit that never thought about this question, but without googling anything, in a brainstorm I would dare to say that those “free electrons” exists and perhaps should be related to some term of the universal constant electric of the vacuum; Just a guess.
 

Yoy can't get an electron flow without a closed circuit, so the free electrons go back into the generator, so it will never run out of electrons.
 

hehe , electrons never end :)
Given the atomic structure of material , electrons are organised on orbits (k,l,m,n,o,p ...) around the nucleus . Usually electrons from last orbits can go from 1 atom to an other since they have more loose connection in the atom . If the circuit is closed , this is what happens , electrons travel in the material from 1 atom to the other so that the structure of each individual atom remains same (total number of electrons ). That's electric current . (the ordinary movement of electrons ). If this path is cut (open circuit > the next atom is not there anymore) the current flow stops . This movement of electrons of in material does not happen by itself , an exterior excitation is needed to produce the displacement. Without that the electrons are rotating around nucleus like usual
 

I agree, when an electron enters a wire, another electron exits the other end.

The reason metals make the best conductors, is because their electrons are easily shared from one atom to another. This creates a kind of 'sea of electrons'. The smallest voltage makes them move.

Carbon is another substance that conducts easily. Its atoms form into molecules that easily share electrons.
 

Hi,

Yoy can't get an electron flow without a closed circuit,
Click to expand...

I'm not sure about this statement.
For a transformer, I agree.

But how does this happen when you fire an electron beam into the orbit? I really don't know..

Klaus
 

Charge carriers can be separated, but not generated. If you strip off electrons from neutral matter, you keep positive excess charge.

In so far, you can't continuously fire electrons without returning them sometimes.
 

KlausST said:
Hi,



I'm not sure about this statement.
For a transformer, I agree.

But how does this happen when you fire an electron beam into the orbit? I really don't know..

Klaus
Click to expand...

that was referred to conductor , you don't fire an electron beam in a conductor, you fire an electron beam in vacuum . Anyway current flow is same even it's about semiconductor, conductor or gas .. electrons don't get wasted and is closed circuit . The electron beam is no exception electrons come from katode to anode , still' closed circuit :smile:
There is conduction by polarisation in dielectrics , that is also closed circuit :)
 

GreenAce92 said:
... but the electrons being generated, where do they come from and can they run out?

"free electrons"
Click to expand...

the electric voltage that is generated (due to the mag field and rotation) drives the current through the circuit.

one is , it is a conductor('conductor/insulator-difference is based on no of electrons available for conduction)
so electrons are available in the materials.

(there is no 'generation of electrons')

those electrons are directed by the voltage generated(electric field) to flow through the circuit.

we say , a current is flowing in the circuit.
 

Though this post is in Elementary electronic questions category but looks I need to do a lot more study in this topic. Thanks sribzf and others for detailed answers. I'm new here.
 

GreenAce92 said:
Pretty sad that I am asking this when I took E&M as a physics major 3 years ago.

"When a conductive wire is in a magnetic field, current is induced"
Right hand rule, point your thumb in the direction of the current, magnetic field around wire.Or is it simply orthogonal to the wire? Anyway...

When you take rotational motion from an outside source whether a spinning turbine or up/down motion of a wave, the wires are cutting through a magnetic field... but the electrons being generated, where do they come from and can they run out?

"free electrons"

Anyway, I'd appreciate a very detailed response.

Thank you
Click to expand...

Nothing much to that question. The charge carriers (electrons) are being pumped around the conductive path. There is no "electron generation". Open the conduction path, no more current.

Ratch

- - - Updated - - -

andre_teprom said:
There is a postulate which says that there no exists magnetic field, nor electric field, but both walk together, which means that one generate other and vice-versa. I admit that never thought about this question, but without googling anything, in a brainstorm I would dare to say that those “free electrons” exists and perhaps should be related to some term of the universal constant electric of the vacuum; Just a guess.
Click to expand...

An energized capacitor maintains an electrostatic field between its plates with no magnetic field involved. A energized coil maintains a magnetic field through its core and external space with no electrostatic field involved. Free electrons are simply electrons that are not attached to an atom. One can strip an electron off its atom. What is left behind is a positive ion.

Ratch

- - - Updated - - -

FlapJack said:
Electrons do move but not very fast, electric power is a complete path. If one electron leaves then another enters.

https://www.physlink.com/Education/AskExperts/ae69.cfm
Click to expand...

No, electric power is the rate at which the circuit dissipates or accumulates energy.

Ratch
 

when a conductor is moved in a magnetic field, the field sweeps many of the outer orbit electrons which are loosely bound to the nucleus, to one end of the conductor. If the circuit is completed then these electrons repel the electrons in the external circuit and a current flows. The electrons do not move very fast, about 25mm a second, but they jump from their present orbit, to the orbit of another atom very quickly (the speed of light). So the apparent speed is very fast, from one electron in to one electron out, though its not the same electron.
The amount of electrons and their energy is determined by the speed and strength of the magnetic field. The amount of loose electrons determines the maximum current (10 ^+23 electrons/second = 1 amp), and their energy determines the EMF (Electro Magnetic Force), which is measured as a voltage.
Frank
 

zsolt1 said:
hehe , electrons never end :)
Given the atomic structure of material , electrons are organised on orbits (k,l,m,n,o,p ...) around the nucleus . Usually electrons from last orbits can go from 1 atom to an other since they have more loose connection in the atom . If the circuit is closed , this is what happens , electrons travel in the material from 1 atom to the other so that the structure of each individual atom remains same (total number of electrons ). That's electric current . (the ordinary movement of electrons ). If this path is cut (open circuit > the next atom is not there anymore) the current flow stops . This movement of electrons of in material does not happen by itself , an exterior excitation is needed to produce the displacement. Without that the electrons are rotating around nucleus like usual
Click to expand...

Charge flows, but not current. Current is charge flow, so "current flow" means "charge flow flow", which is redundant and ridiculous. One should say that current is present or current exists.

Ratch

- - - Updated - - -

srizbf said:
the electric voltage that is generated (due to the mag field and rotation) drives the current through the circuit.

one is , it is a conductor('conductor/insulator-difference is based on no of electrons available for conduction)
so electrons are available in the materials.

(there is no 'generation of electrons')

those electrons are directed by the voltage generated(electric field) to flow through the circuit.

we say , a current is flowing in the circuit.
Click to expand...

Wrong terminology. One should say current exists or is present in a circuit.

Ratch
 

Ratch said:
Nothing much to that question. The charge carriers (electrons) are being pumped around the conductive path. There is no "electron generation". Open the conduction path, no more current.
Click to expand...

It is not completely inconceivable the leakage of some of these electrons from the closed circuit, as well free electron to occur flowing around the space, although I have doubts if they could be easily recombined. Anyway here there are good insights:

 

chuckey said:
when a conductor is moved in a magnetic field, the field sweeps many of the outer orbit electrons which are loosely bound to the nucleus, to one end of the conductor. If the circuit is completed then these electrons repel the electrons in the external circuit and a current flows. The electrons do not move very fast, about 25mm a second, but they jump from their present orbit, to the orbit of another atom very quickly (the speed of light). So the apparent speed is very fast, from one electron in to one electron out, though its not the same electron.
The amount of electrons and their energy is determined by the speed and strength of the magnetic field. The amount of loose electrons determines the maximum current (10 ^+23 electrons/second = 1 amp), and their energy determines the EMF (Electro Magnetic Force), which is measured as a voltage.
Frank
Click to expand...

No, one coulomb per second is one amp, so 6.24E18 electrons per second equals one amp.

Ratch

- - - Updated - - -

andre_teprom said:
It is not completely inconceivable the leakage of some of these electrons from the closed circuit, as well free electron to occur flowing around the space, although I have doubts if they could be easily recombined. Anyway here there are good insights:

Click to expand...

How are free electrons going to leak from their primary conduction path if it is well insulated? In any case, it can be assumed that the leakage will be very, very small. The article does not pertain to this subject because it is talking about high energy radiation within liquid water.

Ratch
 

Ratch said:
Charge flows, but not current. Current is charge flow, so "current flow" means "charge flow flow", which is redundant and ridiculous. One should say that current is present or current exists.

Ratch

- - - Updated - - -



Wrong terminology. One should say current exists or is present in a circuit.

Ratch
Click to expand...

i meant electron flow not current flow ;-) the language barrier again
 

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