The resistance on the wire how big a factor?

[theremart]

Well I was always wondering how big a difference the size of wire matters in getting electricity from point A to point B in the circuit. I was looking at this chart and I found it very interesting to plug different numbers in and to see the results...

American Wire Gauge table and AWG Electrical Current Load Limits

( scroll down to the bottom of the page )

It seems if we are doing a large number of amps the wire thinkness and length is important. The shorter the better. And thicker is better as well...

I was wondering is multi strand better or worse than a solid copper wire? I like multi strand for how flexible it is, but not sure if energy is lost because of the multi strand....


FYI

[RBM]

Hi theremart,

I'm new so I'm interested in how the oldtimers answer your question.

What specifically are you working on ?

I've got formal education and job experience in conventional electronic theory and since I am so rusty in that area I use the web a lot for low level info.

It seems if we are doing a large number of amps the wire thickness and length is important. The shorter the better. And thicker is better as well...

That is correct, but is it all you have to worry about ? DC has no frequency characteristics, but anything non-DC does.

I'm trying to reprogram my mental model regarding EM, but it's a chore. I have a computer and no lab for empirical data generation.

Good Luck.

[theremart]

New to the forum..

Welcome aboard..

[ren]

Hi Mart.

Multi strand bundled together is great for high current. For one, it is alot easier to bend and shape than a solid piece of copper the same thickness. My local store has 20 amp cable and when you remove the insulation you are presented with probably 1000 filar hair fine cable.

You obviously know how resistance is affected when strands are paralleled, so consider the resistance of, say, JB's multi coiler. Lets say he has one coil with 10 strands each 100ft @ 1 ohm. What will his parallel reisistance be of the 10?

And what equivalent gauge would he need if he wanted that result with a single strand @ 100ft? And would the magnetic field produced be stronger with 10 strands or just one?



Regards

[Sephiroth]

the resistance of the wire is an important factor. It is about impedance matching. I never really understood the importance of impedance matching in these circuits, and assumed it only applied to the front end to set the circuit's impedance so that it discharges your primary battery at less than the C20 rate.

but then someone showed me this

Maximum power theorem - Wikipedia, the free encyclopedia

It appears we want the resistance of the coils+wires+diodes to equal the charging batterys' internal resistance. We are talking tiny... my batteries are rated at 8-9 milliohms... the only way to get anywhere near this figure is to use thick wire where ever possible (heavy gauge wire for the coils), use loads of diodes in parallel, and use many windings in parallel.