Electrical current question -- electrons moving through wires....

  • #1
mktsgm
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I have a silly question.

In a simple electrical circuit, we know that the two ends of the wire are connected to different potentials of a battery through the load. Potential difference causes the current flow.

But how the wire comes to know that the other end of it, is connected to different potential, so that current starts to flow through it? In other words 'what' triggers the current flow?
 
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  • #2
Potential difference means there is an electric field between battery electrodes.
 
  • #3
In a conductive material, the electrons will easily move from one atom to another, and they do this randomly with no voltage connected. If you touch the wire to the negative end of the battery, the electrons (which are negative) repel from that. If the wire is not hooked to a circuit, then they will only repel a short distance before the electrons start to "crowd up" and repel back.but if it is connected thwn they keep flowing and repel the electrons in front of them to move through the circuit. The positive end of rhe battery will also attract the negative electrons. This is my simple explanation of what is happening
 
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  • #4
mktsgm said:
But how the wire comes to know that the other end of it, is connected to different potential,
Never anthropomorphise wires -- they hate it when you do that... :smile:
 
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  • #5
berkeman said:
Never anthropomorphise wires -- they hate it whey you do that... :smile:
I do agree with that really, but my view is that when the switch is closed, a wave travels from it on one of
mktsgm said:
I have a silly question.

In a simple electrical circuit, we know that the two ends of the wire are connected to different potentials of a battery through the load. Potential difference causes the current flow.

But how the wire comes to know that the other end of it, is connected to different potential, so that current starts to flow through it? In other words 'what' triggers the current flow?
The battery see an impedance equal to the characteristic impedance of the two wires considered as a transmission line. No matter how short the wire, this is the load that is seen to start with. If the load differs from the characteristic impedance of the wires, a series of echoes occur, and they finally settle to the steady state current value.
(Strictly speaking, the initial step function originates at the switch, not the battery).
 
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