A Hall Effect magnetic linear position sensor is a type of contactless position sensor used to measure linear displacement or position. It relies on the Hall Effect, a fundamental physical phenomenon observed in conductive materials when subjected to a magnetic field and a current flow. The Hall Effect was discovered by Edwin Hall in 1879.
The basic components of a Hall Effect magnetic linear position sensor include:
Hall Effect sensor: This is a semiconductor device, often made of Gallium Arsenide (GaAs) or Indium Antimonide (InSb), which is sensitive to changes in magnetic fields. When a magnetic field is applied perpendicular to the current flow through the sensor, it generates a voltage proportional to the strength of the magnetic field.
Magnet: A permanent magnet is used to create a magnetic field in the vicinity of the Hall Effect sensor. The magnet can be either stationary, with the sensor moving relative to it, or vice versa.
Here's how the Hall Effect magnetic linear position sensor works:
Magnetic field variation: When the sensor is placed in the proximity of the magnet and a magnetic field is applied, the magnetic field strength will vary depending on the position of the sensor relative to the magnet.
Current flow: A current is passed through the Hall Effect sensor, creating a flow of charge carriers (electrons or holes) within the semiconductor material.
Hall voltage generation: As the magnetic field varies due to the relative displacement between the sensor and the magnet, the charge carriers experience a force (Lorentz force) that pushes them towards one side of the semiconductor. This accumulation of charge carriers creates a voltage difference between the opposite sides of the sensor, perpendicular to both the current flow and the magnetic field. This voltage is known as the Hall voltage.
Output signal: The Hall voltage is directly proportional to the magnetic field strength, which, in turn, depends on the position of the sensor relative to the magnet. Therefore, by measuring the Hall voltage, the sensor can determine the linear position accurately.
Signal conditioning and processing: The output from the Hall Effect sensor needs to be conditioned and processed to obtain accurate position information. This involves amplification, filtering, and often analog-to-digital conversion to make the signal suitable for further use by microcontrollers, digital circuits, or display systems.
Hall Effect magnetic linear position sensors offer various advantages, such as non-contact operation (which leads to reduced wear and tear), high precision, long service life, and immunity to dust, moisture, and contaminants. They find applications in various industries, including automotive, industrial automation, robotics, aerospace, and consumer electronics.