The basic idea behind an electro magnets is extremely simple: by passing an electric current through a wire, it is possible to create a magnetic field. Using this simple principle, it is possible to create all kinds of things, including motors, solenoids, read / write heads for hard drives and tape players, speakers, and other things.

What is an electromagnet?

The electromagnet is a device formed by an iron core surrounded by a solenoid (coil). When an electric current passes through the coil turns, a magnetic field is created, which causes the elementary magnets of the iron core to orient themselves, thus being magnetized and, therefore, with the property of attracting other ferromagnetic materials.

Electromagnets have many applications, among which we can highlight: in motors, in bells, in telephones, in the industry of shipbuilding and electromagnetic crane.

An electromagnet starts with a cell or battery (or some other source of energy) and a wire. If you look at any D battery (a flashlight battery, for example), you can see that there are two ends, one marked with a plus sign (+) and the other marked with a minus sign (-). The electrons are grouped at the negative end of the cell and can flow to the positive end with the help of a wire.

If you connect a wire directly between the positive and negative terminals of a battery, three things will happen:

• Electrons will flow from the negative side of the cell to the positive side as quickly as they can.
• The battery will discharge quickly (in a matter of minutes). For this reason, it is usually not a good idea to connect the 2 terminals of a battery directly to each other, normally. You connect some type of charge in the middle of the wire. This charge can be an engine, a lamp, a radio.
• A small magnetic field is created in the wire. It is the small magnetic field that is the support of an electromagnet.

The use of electromagnets offers several advantages:

• It is only the magnetization by electric current that provides you with very powerful magnets.
• You can use a bar of pure iron, which has the property of only magnetizing while the current is passing. And neutralizes as soon as the power is turned off. So, you have a magnet that only works when you want to.

Electromagnets have numerous applications, from delicate installations, such as telegraphs, telephones and bells, to large industrial installations.

James Montano