Unformatted text preview: e proximity sensor to switch through.
There are designs, where the coil is pre-attenuated by means of a small soft
magnetic plate. An externally active magnetic field induces the magnetisation of this
small plate. The oscillator then oscillates and the proximity sensor switches through.
With this type of proximity sensor too, the number of switching zones depends on
the orientation of the magnetic pole axis. One advantage compared with a reed
switch is that only one single switching range occurs if the pole axis of the magnet
runs parallel to the active surface. Fig. 11.2.7: Switching ranges of a inductive-magnetic proximity sensors © Festo Didactic GmbH & Co. KG • FP 1110 171 11. Physical fundamentals Hall sensors The Hall effect was discovered in the last century by E. Hall. He discovered that a
voltage difference is created on the opposite sides of a small thin gold plate,
through which a current passes, if a magnetic field operates vertically to this.
Subsequently, it was discovere...
View Full Document
- Spring '12
- pH, proximity sensors, Festo Didactic GmbH, Festo Didactic GmbH & Co