Coil type characteristics

[pandaemonium]

I was just wondering where I could find some information about the characteristics of different types of coils e.g. winding methods and core materials.

I was looking at some audio links, and it is preferred to use air core coils for lower distortion in speaker crossovers. I don't know why there would be less distortion with an air core coil. With a core of greater magnetic permeability there would be a lower resistance which is also a plus for a speaker crossover (hence, that is why they prefer a large wire gauge) and a smaller coil size.

This got me thinking, what are the characteristics of other coil forms; toroid, bead, rod, etc. and different winding configurations, and why.

I'm not just wondering about coils in use for speaker crossovers, but in general. coils seem to be an important (and often critical) consideration under any application.

Anyone have some links or info for me?

 

[Russlk]

Air core coils are preferred because the inductance is constant, regardless of the current. Iron core coils have varying inductance, decreasing nonlinearly as the current increases. For small currents relative to the core size, the linearity is good and distortion small.

Toroids are good because the magnetic path length is minimized and the leakage flux is small. Rod cores have a large air gap that reduces inductance and linearizes it, and the leakage flux is large.

Check out www.mag-inc.com and www.micrometals.com

 

[pandaemonium]

OK, good info, I checked out the web sites, I can't seem to find the info I want, from the specifics you pointed out, I would like some formulas. Knowing is not enough for me, I 'gotta know every thing' what if I want to make my own coils? From my searches every thing is either trivial or theoretical. I have a book on advanced magnetism but it does not delve into the practical side of the nature of electricity and gause, so I need quite a deal of detail.

Thanks for your patience and help, I know this is a sparse topic.

 

[pandaemonium]

Just a side point, air coil inductance is not constant, it is only assumed so according to temperature and humidity (such are usually constant in a fixed enviroment), but yes, I see your point, that explains it.

EDIT:

Does anyone know where I can find some works of Volta and Tesla online anywhere (not just some lame bios)?

 

[laurent sixtooth]

tesla

try [AARONCAKE.COM] u will find it

 

[pandaemonium]

Sixtooth: AARONCAKE.COM is a spammer site with a lame search engine. I'm sure you didn't send me there intentionally did you?

 

[Phasor]

Sixtooth: AARONCAKE.COM is a spammer site with a lame search engine. I'm sure you didn't send me there intentionally did you?

Try https://www.aaroncake.net/
Note - .net NOT .com