MG Series
METHOD OF MAGNET ACTUATION
There are many ways to apply magnets in Hall-effect sensor applications. The more common methods are described below.
HEAD-ON ACTUATION
For “head-on” actuation, there should be sufficient magnet travel to provide at least 10 % flux overdrive of both maximum operate and
minimum release characteristics of the sensor. The target is centered over the point of maximum sensitivity and is moved “head-on” to the
sensor, then backed off.
Magnetic field
(Gauss)
Figure 21. Unipolar Head-on
G1
G2
D1
D2
Distance
Arrow indicates direction
of magnetic flux
S
Distance
Motion of
magnet
SLIDE-BY ACTUATION
For “slide-by” actuation, the magnet should pass the sensing surface at a distance which provides at least 10 % flux overdrive above
maximum operate. The target is moved across the face of the sensor at a specified distance.
Magnetic field
(Gauss)
Magnetic field
(Gauss)
Figure 22.
Figure 23.
Unipolar Slide-by
(One magnet)
Bipolar Slide-by
(One magnet)
G1
G2
D4 D3 D2D1
Distance
-D2 -D1
D1 D2 Distance
Motion of magnet
N
Motion of magnet
N
S
Arrow indicates
direction of
magnetic flux
Arrow indicates
direction of
Gap
magnetic flux
Gap
Distance
Distance
Magnetic field
(Gauss)
Output voltage
(Volts)
Figure 24.
Figure 25.
Bipolar Slide-by
(Two magnets)
Bipolar Slide-by
(Three magnets)
Distance
Input field
Motion of magnet
Motion of magnet
N
S
Arrow indicates
direction of
Arrow indicates
direction of
magnetic flux
magnetic flux
Gap
Gap
Distance
Distance
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