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You would connect this to an audio amplifier (HiFi amplifier) and then connect your electromagnets to the amplifier output, instead of connecting the amplifier to loudspeakers.
For making electromagnets, find some iron at your local hardware store of the shape you want. If you can not find anything suitable, another source is "Rebar", the metal rods used in the construction industry to reinforce concrete. Try a builders supply outfit. After cutting the iron to size, file off any sharp or rough edges. Then wrap a layer or two of electrical tape around the iron to protect the wire insulation from any rough spots and supply an even base for winding, this is rather important.
For wire to make the electromagnets for the first experiments, probably between 20 gauge to 24 gauge would be a good start. If you can not find a supplier for your location, you could find an old transformer (or even a new one) and take it apart for the wire. Here in the U.S., "doorbell transformers" for electric doorbells are readily available in hardware stores.
Now you need to wind the wire around the iron core. To get the highest number of turns in the smallest space the wire must be wound in even, smooth layers, leaving some extra wire length to make connections to later. Tape a few inches (5cm to 10cm) to one end of the core for one connection. Then start smoothly winding wire around the iron core, keep light tension on the wire so it is tight enough to not slide around. Each turn should be touching but not overlapping the prior turn.
This step is highly recommended but optional if the wire insulation is in good condition, there are no kinks in the wire, and you are being very careful. When you get to the end of a layer, wrap a thin sheet of paper around to cover the layer. Hold it in place with a bit of tape. This provides a stable surface for the next layer and helps avoid short circuits between the layers.
Now start the next winding layer. Make sure the wire winds around the core in the same direction as the previous layer did. Since you are starting at the other end of the core, it is easy to get this wrong if you turn the core around to get a better grip on it. Getting the winding direction the same is needed so that the magnetic field of the layers add to each other. If the winding direction changes between layers the magnetic fields will subtract from each other.
The layers do not have to be the same number of turns. When winding by hand, If you are putting on many layers it is often easiest to have fewer turns on the later layers so the windings do not fall off the ends of the magnet.
When you decide you have enough windings, leave some extra wire for connections and cover the finished coil with a couple layers of tape. This is to provide mechanical protection to the wire and to hold it in place during handling.
Just for your information, the strength of an electromagnet changes directly with the number of turns and the amount of current (Amps) flowing thru it; until it reaches an upper limit defined by the size and material of the core.
For a "First Prototype" this should be enough for you to get a feel of what is needed. Magnetic strength
can be calculated based on the core size and material, the number of turns, and the amount of current thru it. If you get to a point where such calculations are needed, others here are much better at that than I am! Specifically, one
@jim hardy comes to mind.
I know, spelled out in this amount of detail makes the whole thing sound boring and tedious. But if you are even slightly mechanically inclined it's not bad. Making an electromagnet is often a Grade school or Junior High school project!
Have Fun... and keep us updated.
Tom