A Hall Effect linear magnetic position sensor is a type of sensor that measures the displacement or position of a magnetic target relative to the sensor itself. The sensor operates based on the Hall Effect, which is a phenomenon discovered by Edwin Hall in 1879.
The Hall Effect refers to the generation of a voltage across a conductor or semiconductor when it is placed in a magnetic field and carries current perpendicular to the field lines. In a Hall Effect linear magnetic position sensor, the basic working principle can be described as follows:
Sensor Construction: The sensor consists of a thin strip of semiconductor material, often made of gallium arsenide (GaAs) or silicon (Si), with electrical contacts on either end. This strip is placed in a magnetic field created either by a permanent magnet or an electromagnet.
Applying Current: A small electrical current is applied to the semiconductor strip through the electrical contacts. This current flows in a direction perpendicular to the magnetic field lines.
Hall Voltage Generation: When the current flows through the semiconductor strip in the presence of a magnetic field, the moving charge carriers (electrons or holes) experience a force due to the Lorentz force. This force causes the charge carriers to accumulate on one side of the strip, creating a voltage difference between the two sides. This voltage is known as the Hall voltage (V_H).
Proportional to Magnetic Field: The Hall voltage is directly proportional to the strength of the magnetic field applied to the sensor. As the magnetic field changes, the Hall voltage changes accordingly.
Position Sensing: To use the sensor for position sensing, a magnetic target (such as a magnet or a ferromagnetic material) is attached to the object whose position needs to be measured. As the target moves relative to the sensor, the magnetic field experienced by the sensor changes, causing the Hall voltage to vary.
Output Signal: The output of the sensor is a voltage signal that varies linearly with the displacement of the magnetic target. The sensor's electronics can then process this voltage signal to provide a precise measurement of the position.
Signal Conditioning: Signal conditioning electronics, such as amplifiers and filters, are often used to improve the accuracy and stability of the sensor's output signal.
Hall Effect linear magnetic position sensors find applications in various industries, including automotive, industrial automation, robotics, and aerospace, where accurate and reliable position sensing is required. They are particularly useful in harsh environments because they are non-contact sensors and have no moving parts, resulting in improved durability and longevity.