Magnetic Sensors

Magnetic Sensors and Alps Alpine's Magnetic Switches

Magnetic sensors are used to change electrical signals after detecting a magnetic state.
There are various kinds of magnetic sensor, typical ones being Hall sensors and MR sensors.
As implied, Hall sensors make use of the Hall effect, while MR sensors use magnetoresistance (MR) effects.
The Hall effect is the occurrence of a Hall voltage when a magnetic field is applied across a Hall element, whereas magnetoresistance effects are the changes in the electrical resistance of an MR element when a magnetic field is applied across the element.
Alps Alpine magnetic sensors are MR sensors.

Magnetic Sensors and Alps Alpine's Magnetic Switches

Hall sensors and MR sensors use the characteristics of Hall elements and MR elements respectively to convert changes in magnetism into an electrical signal.

The Difference Between Hall Sensors and MR Sensors

A Hall sensor detects the strength of a magnetic field perpendicular to it, whereas an MR sensor detects the angle of a parallel magnetic field.
For that reason, MR sensors generally have a wider detectable area that absorbs layout error.

Magnetic Sensors and Alps Alpine's Magnetic Switches

Alps Alpine MR sensors also have an excellent signal-to-noise ratio as output is at least 10 times higher than a Hall sensor.

Magnetic Sensors and Alps Alpine's Magnetic Switches

Structure of an Alps Alpine Magnetic Switch

A magnetic switch is a switch combined with a magnet that makes use of the above MR sensor characteristics.

Magnetic Sensors and Alps Alpine's Magnetic Switches

Features of Alps Alpine Magnetic Switches

Besides the detectable area and signal-to-noise ratio mentioned above, Alps Alpine magnetic switches enjoy lower sensitivity variation than Hall sensors, allowing consistency even with temperature fluctuation.

Magnetic Sensors and Alps Alpine's Magnetic Switches

Alps Alpine Magnetic Switch Lineup

Alps Alpine magnetic switches come in a number of varieties depending on mounting method (size), drive voltage and output type.

Part number Appearance Size Operating voltage Operating magnetic field Output
HGDESM013A 1.3×0.9×0.525 Typ. 1.8V
(1.6 min. to 3.6V max.)
1.3mT Single-pole, single-output
HGDEPM013A Double-pole, single-output
HGDEDM013A Double-pole, double-output
HGDESM023A 2.0mT Double-pole, single-output
HGDESM033A 3.0mT Double-pole, double-output
HGDEST021B 2.9×2.8×1.1 2.0mT Single-pole, single-output
HGDEPT021B Double-pole, single-output
HGDFST021B Typ. 5V
(4.5 min. to 5.5V max.)
Single-pole, single-output
HGDFPT021B Double-pole, single-output
HGDVST021A 3 to 30V Single-pole, single-output
  • Single-pole, single-output

  • Double-pole, single-output

  • Double-pole, double-output

Here we explained the use of an MR sensor as a switch. Next time we will introduce other applied uses.