AMR Sensors (Magnetic Sensors)Fundamentals of magnetic sensors: differences between AMR sensors (magnetic switches) and Hall effect sensors

Differences between AMR sensors (magnetic switches) and Hall effect sensors

Smaller and thinner magnet design

The magnetic field range usable by AMR sensors is wider for enabling a larger detection range.
The large detection range reduces discrepancies in casing and installation, and a smaller and thinner magnet design than Hall effect sensors can be used.

Differences in magnet direction

In a Hall effect sensor, when a magnet is directly above the sensor, the magnet is placed perpendicular to it. In an AMR, the magnet is placed parallel to the sensor. The detection directions of each magnetic field are different.
Because the magnetic force is strong near the poles of the magnet, if a vertical placement is used, when credit card or other magnetic data is near, it could affect the card data. And so, AMR sensors are advantageous when the magnet will not be placed perpendicularly in electronic devices such as smartphones and notebook PCs. (This does not mean that magnetic data is not lost when a horizontal placement is used.)

Design flexibility

The AMR sensor has multiple available placement patterns for detecting horizontal magnetic fields, and as a result, it has a wide design flexibility.
Hall effect sensors, on the other hand, typically perform pinpoint detection of a magnetic field in the perpendicular direction, and because it is recommended that the magnet be directly above the Hall effect sensor and at close-up range, it has limited design flexibility.

Comparison table of AMR sensors and Hall effect sensors

AMR sensor Hall IC
Detection direction Magnetic resistance effect Hall effect
Sensor Material Ni and Fe Si type
InSb type
Detection Magnet Field Horizontal Vertical
Detection area Wide Narrow