Activation - Using Hall-Effect Switches
A switch requires a Hall IC, a magnet and a means of moving the magnet or the magnetic field. Figures 2, 3
and 4 show several ways by which a magnet can control the Hall IC switch. The following examples are simi-
lar in principle to most real applications. Slide-by, proximity and interrupt configurations represent the three
basic mechanical configurations for moving the magnet in relation to the Hall IC.
Slide-by Switch
In the Slide-by configuration, the motion of the magnet changes the field from North to South within a small
range of motion. This configuration provides a well defined position and switching relationship. The minimum
required motion may be as little as 1 or 2 mm.
Figure 2, Slide-by Switch
In Figure 2A, the South magnetic pole is too far away, so the switch stays OFF. In Figure 2B, the South
magnetic pole turns the switch ON.
Section 3 - Applications
3-3
S
N
A-03
Figure 2A
Linear Slide-By
-100
0
100
200
300
400
500
600
700
800
0
50
100
150
200
250
300
350
Distance in mils (thousandths of an inch)
.050" Airgap
.125" Airgap
.250" airgap
c
S
N
A-04
Figure 2B
Linear Slide-By, Alnico8