Reed Switch Sensor

Reed Switch Sensor

This small reed switch, when exposed to a magnetic field, the two ferrous materials inside the switch pull together and the switch closes. When the magnetic field is removed, the reeds separate and the switch opens. Making this a great option for a non-contact switch.
This switch can carry up to 1.2A.

Reed Switch Activation:

Reed switches are generally used for proximity sensing and are activated by a magnet. They can also be activated by placing them inside an electrical coil. Using a magnet, once brought into the proximity of the reed switch the device will activate. As the magnet is removed from the proximity of the reed switch the device deactivates. However, the magnetic interaction involved in activating the reed switch contacts is not necessarily obvious. One way of thinking about the interaction is that the magnet induces magnetic poles into the metal parts of the reed switch and the resulting attraction between the electrical contacts causes the reed switch to activate:

Another way of thinking about the interaction between a magnet and a reed switch is that the magnet induces magnetic flux through the electrical contacts. When the magnetic flux is high enough, the magnetic attraction between the contacts causes the reed switch to close:

Documents:

• MDSR-4 Datasheet