A Hall Effect angular position sensor is a type of sensor that measures the rotational position of a magnetic target using the Hall Effect principle. The Hall Effect is a phenomenon where a voltage difference is generated across a conductor when it is subjected to a magnetic field perpendicular to the current flowing through it. This effect is widely used in various sensing applications, including angular position sensing.
The working principle of a Hall Effect angular position sensor can be explained as follows:
Sensor Construction: The sensor typically consists of a Hall Effect element, which is a thin strip or semiconductor material (such as Gallium Arsenide) with electrical contacts on either side. The Hall Effect element is mounted on a substrate, and it is protected by an encapsulation to ensure environmental resistance.
Magnetic Target: A magnetic target or rotor is mounted on the rotating shaft whose position needs to be measured. This target is usually a magnet or has magnetic properties. As the target rotates, the magnetic field lines it produces interact with the Hall Effect element in the sensor.
Supply Current: A constant supply current is passed through the Hall Effect element from one electrical contact to the other. This current flows perpendicular to the direction of the magnetic field lines created by the rotating magnetic target.
Magnetic Field Interaction: As the rotating magnetic target creates a magnetic field, the Hall Effect element experiences a force due to the interaction between the magnetic field and the flowing current. This force is referred to as the Hall Effect force.
Hall Voltage Generation: The Hall Effect force results in a charge separation within the Hall Effect element, leading to the accumulation of positive charges on one side and negative charges on the other side. This charge separation creates a voltage difference perpendicular to both the current and the magnetic field, which is known as the Hall voltage.
Output Signal: The Hall voltage is proportional to the strength of the magnetic field and the supply current. As the magnetic target rotates, the magnetic field's strength at the Hall Effect element changes, causing variations in the Hall voltage. The Hall voltage's magnitude and polarity changes correspond to the angular position of the magnetic target, allowing the sensor to measure the rotational position.
Signal Processing: The output Hall voltage is measured and processed by an electronic circuit to obtain the angular position information. Signal conditioning, amplification, and analog-to-digital conversion may be involved in the processing to obtain a usable digital output.
Hall Effect angular position sensors are commonly used in various applications such as automotive systems, robotics, industrial machinery, and position feedback in control systems due to their reliability, non-contact operation, and ability to measure precise angular positions.