This module mainly contains an electromagnet. A magnet that generates a magnetic field from an electric current.
It uses the principle of electro-magnetic. With a straight metal wire passing through the current, the space around the wire will produce a circular magnetic field. In order to concentrate the magnetic field, the coil inside the electromagnet is wound into a coil, and many lines are arranged side by side, so that all the magnetic fields of the coil pass through the center of the coil, forming a strong magnetic field there, which can make it absorb a 1kg ferromagnetic.
When using this module, you can control the electromagnet on and off by controlling the High or Low level on its Signal end.