History

Sturgeon (Sturgeon) electromagnet. AD 1825, Englishman William Sturgeon (William Sturgeon, 1783 年 -1850 years) will pass a current of insulated wire wound rod, invented the electromagnet.
American physicist Joseph Henry Drawer magnets (Joseph Henry 1797 年 -1878 years) after learning the news, the soft iron core coil winding intensive, the use of current small battery powered, will be able to pick up a ton of iron.
Manufacture
Simple homemade electromagnet:

Need wire, nails to make its body; battery or power supply supplied with current.
Note:
To scrape the end enameled paint, or fire.
To enameled wire wound in the same direction.
To the end of enameled knot tied.
Feature
Both ends of the electromagnet and the permanent magnet strongest magnetic force.
Electromagnet magnetic force can be changed.
The direction of the electromagnet can be changed.
Solenoid magnet can control freely.
1822, French physicist Arago and Gay-Lussac found that when the current through the winding which has iron, it can make the iron wire magnetized. This is actually the original discovery of the principle electromagnet. 1823, Sturgeon also did a similar experiment: He is not in a U-shaped iron bar magnet stick around for 18 laps on the bare copper, when copper and voltaic cell is turned on, around the U type iron bar on the copper coils that produce a dense magnetic field, thus making U-shaped iron bar into a "magnet." This magnetic energy than the permanent magnet on the big release times can be, it can pick up more than 20 times its weight of iron, and drum separator  when the power is cut off, U-shaped iron rods on what it could not suck again become an ordinary iron bar. Sturgeon electromagnet invented to make people see the magnetic energy to electrical energy into the bright future of this invention soon in the United Kingdom, the United States and some Western European coastal countries spread. 1829, U.S. scientist Henry Sturgeon electricity electromagnet device made some innovations, insulated wire instead of bare copper wire, copper wire so do not worry about being too close to the short circuit. As the wire with the insulation layer, they can be wound together tightly around the enclosure, the more intensive the coil, the stronger the magnetic field generated, thus greatly improving the ability of electrical energy into magnetic energy. To 1831, Henry trial out an update electromagnet, although its volume is not large, but it can pick up the one-ton iron. The invention also enables the electromagnet generator power has been greatly improved.