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Electromagnet projects? I need some good ones. Answered

I have a whole lot of copper I have been collecting over the months. Some of many gauges. I even collect the field coils in universal and 3 phase motors.

Anyway, if any of you guys have any ideas about anything to make, or even anything INVOLVING electromagnetic's, give me a holler.
Also, I don't want anything non-electrical related. Such as making pretty ponies out of copper wire.
And perhaps you can throw me some other hints, and tips. I considered myself a professional back when I was like 12-13 just because I knew how everything worked. Well, I was a retarded 12 year old. I thought I knew everything and that people were wrong about certain things until I learned about Ohm's law and many other laws regarding electricity. I know a good deal now, but I need some help and tips. 

If you have any formulas that I need to study in order to fully know how everything works, and works together, please, I am more than interested to learn about it. I can only do Ohm's Law, as that is basically the only one that I know. I know how to convert amps to watts, and whatnot. But basically, just need a heads up on how to learn this. As I will probably be studying Electrical Engineering as I continue my journey through high school.

I don't know if I am the only person on here that awkwardly likes messing around with stuff, and don't know how to build it.. I just basically like to hook things up to electricity and watch it do it's magic. Basically that's what my whole life was doing, applying electricity and freaking out about how amazing it is.

Basically that's my life story.. In a question that I asked, and now am off topic. Thank's for reading my entirely boring passage. 


I forgot to mention it, but one of the practical things you can do with a coil of wire and understanding of self inductance,
is to build yourself a metal detector.

Those I am thinking of are based on the "beat frequency" you get from mixing the signals produced by two oscillators with almost the same frequency.  One has a fixed frequency, f1. The other, f2, varies with the self-inductance of the search coil.  The beat frequency is just the difference of these two frequencies |f1-f2|. The acronym BFO stands for, (b)eat (f)requency (o)scillator, and you'll see that word come up a lot in those search results.

I think there is a one word answer for the "formulas that [you] need to know in order to fully know how everything works" , and that one word is "physics". This is probably a word you have heard before, and also a word that you will hear again, and again... especially if you're going to be studying electrical engineering.  As a foundation for that course of study, you will be required to take some classes in introductory physics.  Usually the first of these is an introduction to classical mechanics, and the second course is an introduction to electricity and magnetism.

The  "laws" of electricity and magnetism most relevant, in my opinion,  to playing with coils of wire, are Ampère's circuital law , Faraday's law of induction, and Ohm's law (which you already mentioned). 

In summary, for a given coil of wire, the results of these laws are as follows:

Ampere's law tells you that the magnetic field strength, B, in the center of your coil, is proportional to N*I, where N is the number of turns, and I is the current through each turn.  Ampere's law tells you about the coils ability to produce magnetic fields.

Faraday's law tells you that there is a voltage induced in this coil, in response to changing magnetic field.  Again this is proportional to the number of turns. V = N*A*(dB/dt). That is, Faraday's law tells you about a coil's abilty to respond to, or to receive, changing magnetic fields.

Self inductance depends on both Ampere's law and Faraday's law, and as a result, it typically includes a factor of N-squared (the number of turns squared).

Ohm's law tells you how much power is lost to electrical resistance, and this is just I2 *R, where I is current, and R is the total resistance of the length of wire that makes up the coil.

If you want more than just the executive summary, you can find it here:
among other places.  I just sort of picked that one from a cursory glance at all their physics classes, here:
because that one appeared to have the most little resource icons, e.g notes, example problems, multimedia, etc, in the column on the left.

BTW, the vector calculus (divergence, curl, dot products, etc.) might look a little scary at first, but it becomes less scary as you learn what those things mean, and even if you never fully grasp it, for most practical problems like those dealing with a single coil of wire, all the vector calculus can be reduced to simple formulas involving just a few scalar quantities, e.g. current and voltage and the component of B normal to the coil.

To change the subject a little bit, I built a magnetic levitator toy one time, but all I ever posted about it was a single picture and circuit diagram, in response to this question:
Someday, if the spirit moves me, I might actually write a more detailed instructable about how to do that, as there seems to be some interest in the subject.


6 years ago

Make two resonant flat coils to float aluminum plates.
You will need large AC condensers.


Apparently I don't have the technical expertise to do that. And the technology...

If you are up to the challenge, a cool project involving an electromagnet is a levitator. I'm referring to the type that use a sensor to determine the position of the levitating object, and then controlling the current throught he coil to keep the object in one position, without falling or getting stuck to the magnet.

You'll need to learn about electronics as well to get such a project working. There are some examples of levitators on this site to help get you started.

Levitators are not easy. However, I have a question for you.... wait a second... ITS YOU AGAIN! I remember you, cleverly answering my questions a while back... ANYWAY..

I guess this would count as levitation, except without sensors: I was trying to make a tube float perfectly in the center of another one. I have two, 2 foot PVC pipes, one slightly bigger than the other, and I was trying to wind a coil around the bigger pipe and another coil on the smaller one to simulate a levitation effect.

But I'm afraid it's much more complex. Maybe you have the answer to that question.. Bigger tube = coil wound around it beginning to end; Smaller tube = coil wound around it beginning to end;

I have made one, but it didn't have enough electromagnetic power to float the tube. I still can't figure out how to repel two magnetic fields (Copper ones.)