Permanent magnet

• Retain their magnetism for a long time.
• Prepared from hardened steel and certain alloys of nickel and cobalt.
• Alnico is widely used in electrical instruments, earphones, loud speakers, telephone reciever, small dc motor.
• Permanent magnet should not be heated up or hammered. otherwise it will be demagnetized.
• if a pair of magnets is kept, the keepers should be used and magnet should be kept facing the opposite polarity.