China Neodymium And Ferrite Magnets Manufacturer & Supplier 
Hall effect sensors are usually used to detect the presence or strength of magnetic fields, they need to be used with magnets in many applications, such as in motor position sensing, flow measurement, proximity switches and other scenarios, today I recommend 3 magnet sizes suitable for sensing chip manufacturers such as iC-haus/AMS/MagnTek.
Radial 2-pole round neodymium magnet for Hall effect sensors
Radial 2-pole round magnet is the magnetization direction along the direction of the magnet radius, this magnetization of the magnet side (radial direction) magnetic field is strong, and 6x2.5mm, 8x2.5mm, 10x2.5mm these 3 specifications are commonly used in magnetic sensors, the performance of the general N35H will be enough, temperature resistance of 120 degrees Celsius.
Radially magnetized round neodymium magnets
The distance and relative position between the Hall sensor and its companion magnet affects the sensor's output signal; the closer the distance, the greater the Hall voltage.
Example of the application of a Hall sensor with a radial 2-pole circular magnet;
A magnet is mounted on the motor shaft and a Hall sensor is fixed to the motor housing to detect the magnet's rotational frequency to determine the motor's speed.
In an encoder, the combination of a radial 2-pole magnet and a Hall sensor allows precise measurement of the rotational position.
In addition to neodymium magnets, you can also choose ferrite (lower cost, but slightly weaker magnetic properties than NdFeB), samarium cobalt (performs well in high-temperature environments), depends on specific magnet strength required, When using them, make sure that the distance and position between the magnets and the Hall sensors are appropriate to get the best detection results.
Finally, a few important words: different Hall sensors and application scenarios may require magnets of different shapes and sizes, such as cylindrical, square or ring. Different types of magnets perform differently at different temperatures, and it is necessary to choose a magnet material that is stable over the operating temperature range. For rotary encoders or position sensors, the more poles the magnet has, the higher the angular resolution the sensor can detect. For example, magnets with multiple pole pairs can provide finer angular measurements.
Magnets suitable for Hall sensors;
Introduction to other Hall sensor magnets;
Which side of the magnet should be induced by the Hall sensor?
Can the hall sensor be oriented sideways towards the magnets?
Sensing distance between Hall chip and magnet and magnet selection