The Hall effect is named after Edwin Hall, who discovered in 1879 that when a magnetic field passes through a current-carrying conductive plate in a direction perpendicular to the plate’s plane, a voltage potential arises across the plate. The Lorentz force, depicted in the upper panel, is the underlying physical principle underpinning the Hall effect. When an electron moves in a direction that is perpendicular to the applied magnetic field, B, it is subjected to a force called the Lorentz force, which is normal to both the applied field and the current flow.
A Hall effect sensor (or simply a Hall sensor) is a type of sensor that uses the Hall effect to detect the presence and amplitude of a magnetic field. The Hall sensor’s output voltage is proportional to the strength of the field. In this article, you’ll learn the definition, applications, diagram, working principle, advantages, and disadvantages of the Hall effect sensor.
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What is a Hall effect sensor?
A magnetic sensor is a form of a Hall Effect sensor. A Hall Effect sensor is a transducer that responds to changes in a magnetic field by varying its output voltage. It is an electronic device that detects the Hall effect and converts its findings into electronic data, which can then be used to turn a circuit on and off, measure a fluctuating magnetic field, be processed by an integrated computer, or be shown on an interface.
When a magnet is placed perpendicular to a current-carrying conductor, the electrons in the conductor are pushed to one side, resulting in a potential difference in charge (i.e. voltage). The presence and amplitude of a magnetic field near a conductor are thus indicated by the Hall effect.
Applications of hall effect sensor
The followings are the common applications of the Hall effect sensor:
- Hall sensors are utilized in applications such as proximity sensing, location, speed detection, and current sensing.
- Hall sensors are often used to time the speed of wheels and shafts, such as for tachometers or timing the ignition of internal combustion engines.
- They are used to detect the position of the permanent magnet in brushless DC electric motors.
- The detection of a moving element in place of a mechanical limit switch is a common application. The indexing of rotational or translational motion is another common use.
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Diagram of a hall effect sensor:
In the working of a Hall effect sensor, a thin rectangular p-type semiconductor material such as gallium arsenide (GaAs), indium antimonide (InSb), or indium arsenide (InAs) passes a continuous current through itself to form a Hall Effect Sensor. The magnetic flux lines exert a force on the semiconductor material when the device is placed in a magnetic field, deflecting the charge carriers, electrons, and holes, to either side of the semiconductor slab. The magnetic force that charge carriers encounter as they pass through the semiconductor material causes them to move.
The build-up of charge carriers creates a potential difference between the two sides of the semiconductor material as electrons and holes migrate sidewards. The existence of an external magnetic field at right angles to the semiconductor material then affects the passage of electrons through it, and this impact is higher in flat rectangular-shaped material. The Hall Effect is the result of employing a magnetic field to generate a quantifiable voltage.
Magnetic flux lines must be perpendicular (90o) to the current flow and of the correct polarity, often a south pole, to generate a potential difference across the device. The Hall effect reveals the type of magnetic pole as well as the amount of the magnetic field. A south pole, for example, causes the device to create a voltage output, whereas a north pole has no impact. When there is no magnetic field present, Hall Effect sensors and switches are meant to be in the “OFF” (open circuit status). When exposed to a magnetic field of appropriate strength and polarity, they turn “ON” (closed-circuit condition).
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Watch the video below to learn more about the Hall effect sensor:
Advantages and disadvantages of a hall effect sensor
Below are the benefits of a Hall effect sensor in its various applications:
- When compared to electromagnetic switches, it is quite inexpensive.
- It is feasible to operate at a high frequency.
- It can be utilized for a variety of purposes, including displacement, position, and proximity sensors.
- It is strong and durable, and it can withstand harsh conditions.
- Because they are resistant to humidity contamination, they are ideal for a variety of applications.
- There is no difficulty with contact bounce.
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The only disadvantage of the Hall effect sensor is due to misalignment of contact in the Hall element and piezo-resistive effects, the sensor becomes weak.
A hall effect sensor (or simply a Hall sensor) is a type of sensor that uses the Hall effect to detect the presence and amplitude of a magnetic field. The Hall sensor’s output voltage is proportional to the strength of the field. That’s all for this article, where the definition, applications, diagram, working, advantages, and disadvantages of a Hall effect sensor are been discussed.
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