Electromagnets ç£å ´ã³ã¤ã« electromagnet ç£å ´ã³ã¤ã« ç£å ´ã³ã¤ã« ç£å ´ã³ã¤ã« Electromagnet, Electromagnetic Coil and Permeability ç£å ´ã³ã¤ã« ç£å ´ã³ã¤ã« Electromagnet, Electromagnetic Coil and Permeability