AG920-07E NVE, AG920-07E Datasheet - Page 111

• Manufacturer Part Number: AG920-07E
• Description: KIT EVALUATION GT SENSOR
• Manufacturer: NVE

Specifications of AG920-07E

• Sensor Type: Magnetic. GMR (Giant Magnetoresistive)
• Interface: Analog
• Embedded: No
• Utilized Ic / Part: ABL & AKL Series GT Sensors
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Supply: -
• Sensitivity: -
• Sensing Range: -
• Other names: 391-1063

For example, tolerances on the placement of the magnet relative to the sensor are not perfect, and any
slight variation in the placement of the magnet can lead to offset problems; see the drawing below:
Generally the magnet is glued in place; this can lead to tilting of the magnet with respect to the sensor,
introducing more variations in the field at the sensor, and more offset problems, as well as potential
glue joint problems. Furthermore, the composition of most inexpensive magnets is not particularly
uniform, and many have cracks or other mechanical imperfections on the surface or internally that lead
to a non-uniform field. Most permanent magnets have a temperature coefficient, and some can lose up
to 50% of their room temperature strength at 125°C. The following drawing shows the effects of
temperature added onto an imperfect bias. The offset of the sensor varies with temperature as shown:
Finally, as the airgap changes, the magnetic field at the sensor also changes. So, the magnetic field at
the sensor will vary from one installation to the next, and if the gear has runout, wobble, or expands
with temperature, the output signal and offset of the sensor element will vary.
GMR Senso r
Resistors R3, R4
GMR Senso r
Resistors R3, R4
www.nve.com
Direction of Sensitivity
Direction of Sensitivity
Magnet
Magnet
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- 111 -
GMR Senso r
Resistors R1, R2
GMR Senso r
Resistors R1, R2
25C
125 C
Application Notes
Voltage Output of
GMR Bridge
Voltage Output of
GMR Bridge
Offset Induced by
A symmetry of Magnet
and Sensor Elements
25C
Rotation
125 C
Rotation