An apparatus for generating an electromagnetic power. In the core of their power to match the external wound conductive coil, which has a current through a coil like a magnet with magnetic, it is also called solenoid (electromagnet). We usually shaped or plate shape which is made to make the magnetic core more easily. Further, in order to demagnetize the electromagnet is turned off immediately, we tend to use a faster degaussing soft iron or silicon steel making material. Such a magnetic solenoid when energized, the magnetic power will disappear. Electromagnet has an extremely wide range of applications in our daily life, due to its invention also enables the generator power has been greatly improved. When the core is inserted inside the solenoid is energized, the solenoid is energized the magnetic core magnetization. The core is magnetized into a magnet, so that due to the superposition of two magnetic fields to each other, thereby greatly enhancing the magnetic solenoid. To make a stronger magnetic solenoid, the core is usually made of horseshoe. But pay attention to the core of the coil around the horseshoe to the contrary, while clockwise, the other side must be counter-clockwise. If around the same magnetization of the two coils cancel each other core, the core was not magnetic. In addition, the electromagnet with a soft iron core to do, I can do without steel. Otherwise, once the steel is magnetized, and not the long-term magnetic demagnetization, its magnetic strength can not be used to control the size of the current, and lose the advantages of the electromagnet due. Electromagnet can pass current to generate a magnetic device, is a non-permanent magnets, you can easily start their magnetic or eliminated. For example: the use of a large crane to lift the electromagnet will scrap vehicles. When the current through the wire, it will generate a magnetic field around the wire in. Application of this nature, when the current through the solenoid will be made in a uniform magnetic field inside the solenoid. Assuming the center of the solenoid into the ferromagnetic material, the ferromagnetic material is magnetized in a magnetic field and will be greatly enhanced. Solenoid has many advantages: the presence or absence of magnetic solenoids can be turned on and off a current control; size of the magnetic strength of the current can be used or coils to control the number of turns; magnetic properties can also be controlled by varying the size of the size of the control current resistance ; its poles can be controlled by changing the direction of the current, and the like. Namely: the magnetic strength can be varied to control the presence or absence of the magnetic direction of the magnetic pole can be changed by a current of magnetically vanishes. Electromagnet is magnetic effect of current (electricity magnetism) an application, closely connected, such as electromagnetic relays, electromagnetic crane, maglev trains, magnetic flowmeter with life.