Do electrons flow through or around a copper wire?

[MalfunctionProne]

Originally Posted By: razel
Originally Posted By: Ed_Flecko
Originally Posted By: javacontour
For DC, it uses the entire wire. With AC, you get some skin effect.

The reason to make stranded cable for DC is the ease of bending it. It makes no difference electrically in jumper cables, a DC application.


So, assuming the wire gauges were identical, you're saying that a cable made of a single, solid copper wire should flow just as much electricity as a cable made up of multiple copper wires?

So the only advantage the cable made of multiple strands has is that it's more flexible?

Ed


javacountour has already summarized it well and answered your question. No need to double check since brevity and simplification is a sign of deep knowledge.

If you double check his/her wisdom everyone else will just repeat or detail the reasons then it'll turn into rocket science. Well actually electricity is far more complex than rocket science. It's far more valuable too in our Information Age since electricity is it's blood.

Well hopefully you learned enough so you can make a wise decision over the price difference in a $20 vs. $40 jumper cable.

The $40 one is better, right?

 

[KrisZ]

Originally Posted By: MalfunctionProne
The $40 one is better, right?


Yes, it will flow twice the electrons of a $20 cable.

 

[grumpyoldman]

Originally Posted By: javacontour
For DC, it uses the entire wire. With AC, you get some skin effect.

The reason to make stranded cable for DC is the ease of bending it. It makes no difference electrically in jumper cables, a DC application.


This is right.

My recommendation on jumper cables is, in this order:

- good clamps
- good length
- flexible (easy to work with; won't fall off)
- beefy gauge

Since the clamps attach to your battery terminals in just a few tiny spots, they are the highest resistance parts of the circuit, in series with the R of the wire itself. I'll let others who know more than me chime in on the ideal gauge, but 8 has always worked well for me.

 

[RF Overlord]

{wouldn't let me delete}

 

[RF Overlord]

Originally Posted By: KrisZ
Originally Posted By: MalfunctionProne
The $40 one is better, right?


Yes, it will flow twice the electrons of a $20 cable.
Only if the clamps are twice as big...

 

[Lapham3]

Now that the theory is covered, and maybe next ? is who makes the 'good stuff'. I'll just say that some heavy gauge 20 foot guys from Carrol Cable are the best that I've seen and used=higher price, but high quality in everything as well as very flexible in the cold. Should add that my sets are 70's vintage

 

[Garak]

For those interested more in CrawfishTails's remarks about speed of propagation versus the speed of the actual electrons, along with more of the math that 440Magnum pointed out, take a look at Heaviside's equations.

 

[HerrStig]

Originally Posted By: Garak
For those interested more in CrawfishTails's remarks about speed of propagation versus the speed of the actual electrons, along with more of the math that 440Magnum pointed out, take a look at Heaviside's equations.
The old illustration of the line of golf balls hanging from strings and almost touching applies here. The end ball delivers a good shot to the next in line and most of that energy is transferred to the last ball, though the balls in the middle don't move very much.
When AC above 30 cycles or so is studied the cable carrying it starts to act like an radio frequency energy transmission line, because it IS. There's a difference in the behaviour of AC at 50 cycles and at 60. Radiation loss from the line can happen at 60 cycles if the line is long enough. There have been some experiments with high voltage DC lines to try to mitigate this.

 

[turtlevette]

Originally Posted By: CrawfishTails
Copper and other conductors are already loaded with electrons throughout their cross section, and those actually jump from atom to atom, so the answer is "through". Google "speed of electricity".


The current density is higher the further you get from the center of the wire. The effect is greater the higher the frequency. If you look up resistance tables of standard wire sizes there will be a DC resistance then a 60hz resistance. The 60hz resistance is higher.

If you have semiconductor material, you'll have electrons moving one way and holes moving the other.