Hall Effect Sensor
A semiconductor element that converts the presence or strength of a magnetic field into an electrical signal without contact. In the DC driver world you meet it in two places: as a switch type for sensing an end position or speed with a magnet, and as a linear type that measures the magnetic field of the current flowing in a conductor to provide isolated current measurement.
When current flows through a Hall element and it is exposed to a perpendicular magnetic field, a small voltage appears at its edges. This voltage is proportional to the field strength.
- Switch type: Changes its output above a certain field strength. Since there is no mechanical contact its life is longer than contact-based solutions and it is not affected by dust and moisture.
- Linear (current sensor) type: The output voltage is proportional to the current and the measurement circuit is electrically isolated from the power circuit. Unlike a shunt resistor it produces no loss in the measurement path.
This is why a Hall-based sensor is preferred for isolated measurement of DC current: a classic current transformer requires a changing field and cannot see a constant DC field. If isolation is not required, the same current can also be measured across a shunt resistor.
The sensor inputs of the KS250 are defined so that they can work with Hall type feedback elements. When choosing the sensor, verify whether the output is NPN or PNP and that the supply voltage matches the line the driver provides.
The context in which this term is used: DC Motor Driver Selection Guide