Simple magnetizer circuit one b

After some small magnets lose their magnetism, they can be re-magnetized with a simple homemade magnetizer.
  Find a used AC contactor, such as CJ10-60~150A and other models (220V or 380V can be used), remove the straight
armature, and only use the mountain-shaped iron core. String a diode and a fuse in the coil loop to form a magnetizer, as
shown in Figure 10-42. Picture (a) is suitable for magnetizing bar magnets, and picture (b) is suitable for U-shaped magnets by setting soft iron.
When magnetizing, use ends A and B to touch the AC power supply of 220V (when the rated voltage of the coil is 220V) or 380V ( when the rated voltage of the coil is 180V) (pay attention to safety). Sparks will be generated when touching. As long as you touch 1 , 2 times is enough. After waiting for more than ten seconds, touch it 1 or 2 times again to complete the magnetization. Then let it sit for a few hours before removing it (this works better).