You know that it is another geometry, whose formulae are distinctly different, so it is not clear how this fits into the case discussed so far, the coil.
Anyway, it may not have been clear that it is up to you to do the next step: Make experiments, tabulate results, and compare each case to determine which one suits your need. At least it is how I do.
Not different at all, i am considering both flat spiral coil as well as longer solenoid.
This was the first mention you made of the spiral geometry so far.
Let's agree, this thread seems like not converging to anywhere.
Bring us results of your experiments, as well as drawings of the actual apparatus you are measuring.
The answer is of course yes it is less to your 'shouted' question.I want to clear one important detail up.
DO OUTER WINDINGS OF A PANCAKE COIL CONTRIBUTE LESS TO THE FIELD IN THE CENTER OR NOT?
If we look at the formula for a field of a single loop we can see flux gets weaker with bigger radius.
B = u0 x I / 2R
But isn't it logical flux from outer windings must also pass through the center? Where else would it pass?
I mean no matter how wide we make the "pancake" those most outerwinding will still converge through the central gap and thus increase the central flux just as much.
OR??
The answer is of course yes it is less to your 'shouted' question.
Field strength is prop. to radius i. e. distance... 2πr
Field density is inverse prop to area or .. πr^2
So for a larger loop, field density (tesla's) at centre is prop. to 1/r
Why is this hard to understand?
(Same answer)
You may be confusing between total flux, and flux density. Tesla is a unit of flux density
I admit to have wrongly used the term flux for flux density B in some places.
The difference is relevant in so far that the ampere-turns generate the flux which doesn't depend on the radius of the ring current, but the flux density in the center does.
Your question has been clearly answered, the outer pancake coil windings contribute less to the center flux density, so do the outer windings of long coil. That's the reason why the optimal coil geometry is neither pancake nor long single layer but some kind of cylinder as previously stated.
"Why do you assume all the flux "rushes" to the exact center? Flux is highest near the current flow and decreases with distance away.
This thread is now a waste of time, and I for one am exiting.
... View attachment 154005 ....Thread is surely not waste of time, your contributions to it surely are.
This drawing does not represent a simple coils' (whether planar, spiral, cylindrical) magnetic field lines. It is clearly a pictorial of some other configuration/ other device.
Since you are basing most of your theories on this pictorial, it would be useful for this forum to know where it is obtained from and what does it refer to ?
Flux is highest near the current flow and decreases with distance away.
Are we to assume outer coils not only contribute less to flux density in the center but also produce less flux in the first place?
minimum field strength always occurs on the center line. And for a single coil configuration (unlike e.g. Helmholtz coil) on the outer points, in other words the minimal field strength points are r=0, z=+/- d/2.
field in the center is always minimum.
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