When the Hall IC and magnet are fixed, the Hall IC can be activated using a ferrous vane. This system,composed of a Hall IC, magnet and ferrous vane is called an interrupt switch. In the interrupt switch the magnet is positioned so the South pole turns ON the switch while the Hall IC and magnet positions are fixed relative to each other. When a vane made of a ferrous material is placed between the magnet and Hall IC, the magnetic field is shunted or reduced to a very small fraction of the maximum field, turning the switch OFF. This vane is shown in Figure 5 as a notched interrupter. This switch is an effective way to sense position.
In Figure 5A, the South magnetic pole is exposed to the Hall IC through the vane, so the switch turns ON. In figure 5B, the switch turns OFF because the magnetic field is blocked by ferrous material. |