The magnetic field that is formed by a permanent magnet and a conductor with a current has the same nature. A magnetic field occurs only if current flows through a conductor. The simplest electromagnet consists of a ferromagnetic core, over which a wire is wound. The ferromagnetic core allows a thousand times to increase the magnetic field of the coil, which is also called the solenoid. The magnetic field has a north and south poles, which are from the direction of flow of electric current. For the first time, magnetism began to be widely studied by the Danish scientist Oersted.