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

Differences from reed switches

Low variation in sensitivity, compact size, and impact resistant

Compared to reed switches, AMR sensors have less variation in sensitivity for enabling wider flexibility in magnet and sensor placement designs.

Also, their small size enables reduced sizes and surface installation for PCBs for reduced installation costs. In addition, AMR sensors can be handled easily because they are more resistant to vibrations and impact than reed switches, and their no-contact design allows a longer lifespan.

Magnetic field detection direction is the same

Because the magnetic field detection direction is the same, magnets that were used in reed switches may be able to be used without modification in AMR sensors in some cases.

However, be aware that, because the individual switches in AMR sensors have their own circuits, they require a power supply for operation, and consequently, AMR sensors may have different numbers of wires and current consumptions.

Comparison table of AMR sensors and reed switches

AMR sensor Reed switches
Minimum package size of AMR sensor: 1.45×1.45×0.55㎜
Ease of installation
No special processes such as bending of lead terminal and PCB grinding required
Variation in sensitivity
Proprietary sensitivity adjustment function enables less variation in sensitivity
High resistance to vibrations and impact
Due to their structure, reed switches are sensitive to vibrations and impact
Design flexibility
Wider design flexibility due to smaller size and less variation in sensitivity
Product lifespan
AMR sensors do not have contacts, and so contact lifespans are not an issue
Directionality Narrow
*Directionality is adjusted
Line system 3 wires
2 wires
Bounce time None
Allows high-speed processing
Maximum drive frequency 1~2 kHz 500Hz