Magnetism - Toroid Ferrite Cores

Hello all.

First, I should say - I attempted to post this in the research forum but it does not allow me to post there. Shame... I would have liked to have my post open for continual discussion of my ideas and exploitations.

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As I've mentioned recently - I'm playing around with a 3D Printer and Magnetism for my own personal experimentation and enjoyment. I'm going at this as a complete novice and the terminology involved is very dumbed down.


Currently, I'm trying to understand Toroid Ferrite Cores. I do understand that they're simply an inductor that allows DC currents to pass through while filtering AC current but I'm curious about it's application with magnetism. Perhaps someone who's more familiar with these little fellas could give me some clues as to what's what. Warning: This is probably a very stupid question but I would very much appreciate the answer, no matter how patronizing or any jabs you may want to take at my intelligence on the subject. Knock yourself out if need be. That being said... here goes:


If I were to take a magnet and fit it neatly and snugly inside of a Toroid Ferrite Core, what exactly could it be used for? What actually happens? I'm not sure how to inquire on exactly what I'm looking for. Patience please.

I imagine it's basically iron around a magnet but what science actually takes place? In addition, if any, does the ferrite simply act as part of the magnet or would it dampen the magnetic field around the magnet some?

I'm attempting to dampen the field around the magnet save only at the poles.


Thanks in advance!

a reply to: StallionDuck

does the ferrite simply act as part of the magnet or would it dampen the magnetic field around the magnet some

You can see the ferrite as a magnet opposing the magnet in the center. It will weaken the field of the magnet. Or more correctly, the total magnetic field will be the sum of ferrite ring and magnet core fields. You can picture it as magnetic field lines going from magnet core into ferrite ring.

a reply to: moebius

Thanks for the info!

This would be counter productive to what I want to do. If I'm reading you right, it would weaken the overall field causing the magnet to have less strength at the poles. So basically, I'm making the magnet larger but dividing the force between the two combined. Like going from a 6x3 magnet to a 8x3 magnet (core = 2x3) of a similar strength.

a reply to: StallionDuck

Print a long 2 piece barrel in 2 halves you can place lots of toroids in and make a railgun to fire stuff at stuff.

yea yea do it do it!

Howdy...guitar pickup maker here, so I know a little about magnets, electromagnets, and inductors.

A two-pole magnet relies on the flux differential (magnetic strength) across its poles to generate the field around itself. What this means is anything that interferes with the flux anywhere in proximity of its mass will negatively affect the strength of the field near its poles.

Do you have magnetic viewing film? If not--get some. It's cheap and it allows you to visualize the field around a magnet. It's nowhere nearly as accurate as a gauss meter, but it will help you understand how different materials in proximity to a magnet affect the field.

It could be used for nothing when static. By moving the magnet you can induce a very, very small charge in the choke/inductor.

a reply to: StallionDuck

originally posted by: TheTruthRocks
Howdy...guitar pickup maker here, so I know a little about magnets, electromagnets, and inductors.

A two-pole magnet relies on the flux differential (magnetic strength) across its poles to generate the field around itself. What this means is anything that interferes with the flux anywhere in proximity of its mass will negatively affect the strength of the field near its poles.

Do you have magnetic viewing film? If not--get some. It's cheap and it allows you to visualize the field around a magnet. It's nowhere nearly as accurate as a gauss meter, but it will help you understand how different materials in proximity to a magnet affect the field.

A kindred spirit. I have handmade a few guitars and have worked on tube equipment for a long time. I had no idea there was a film that would let you see the magnetic field, that's awesome! The way a transformer or coil works has always amazed me.

a reply to: nerbot

That's an awesome idea. So the magnet would be the bullet?

a reply to: TheTruthRocks

I do have some!

Thanks for the info!


So there isn't anything that can block the field around the midsection of the magnet only exposing the two poles without diminishing the strength of the magnet? That's what I'm looking to accomplish.

I don't think so. A paramagnetic material, such as copper or aluminum, might have an effect on a monolithic permanent magnet.

But Lenz's Law rules here, and as hombero states above, the magnetic field must be moving in relation to the ferrite toroid for it to induce current in the material.