- Edwin Hall discovers Hall voltage in 1879. The nature of the current in a conductor causes the Hall Effect. This Hall Effect theory was used in many inventions. This theory is also used in current sensors, pressure sensors, and fluid flow sensors, among other things. The Hall Effect sensor is one such invention that can measure magnetic fields.
Hall Effect Sensor
- The linear transducers used to measure the magnitude of the magnetic field are known as Hall-effect sensors. These sensors, which operate on the Hall Effect principle, generate a Hall voltage when a magnetic field is detected, which is then used to calculate the magnetic flux density.
- Linear sensors are capable of measuring a wide range of magnetic fields. Aside from magnetic fields, these sensors can detect proximity, position, and speed. The output voltage of these sensors is directly proportional to the magnitude of the magnetic field.
Working Principle of Hall Effect Sensor
- The Hall voltage principle is used as a working principle of the Hall Effect sensor. When electricity is applied to a thin strip of a conductor, electrons flow in a straight line. When this charged conductor comes into contact with a magnetic field that is perpendicular to electron motion, the electrons are deflected.
- Some electrons are collected on one side, while others are collected on the other. As a result, one of the conductor’s planes is negatively charged, while the other is positively charged. This results in a potential difference and the generation of voltage. The Hall voltage is the name given to this voltage.
- The electrons continue to move from one side of the plane to the other until there is a balance between the force applied to charged particles by an electric field and the force that caused the magnetic flux that caused this change. When this separation comes to an end, the hall voltage value at that point gives the magnetic flux density.
- Hall Effect sensors are classified into two types based on the relationship between hall voltage and magnetic flux density. The output voltage of the linear sensor is proportional to the magnetic flux density. The output voltage of the threshold sensor decreases sharply with increasing magnetic flux density.
- Hall Effect sensors are analogous to linear transducers. To process the sensor output, a linear circuit is required that can provide a constant driving current to the sensors while also amplifying the output signal.
Applications of Hall Effect Sensor
The applications of Hall-effect sensors are as follows.
- When combined with threshold detection they act as a switch.
- These are used in ultra-high-reliability applications such as keyboards.
- Hall Effect sensors are used to time the speed of wheels and shafts.
- These are used to detect the position of permanent magnets in brushless electric DC motors.
- Hall Effect sensors are embedded in digital electronic devices along with linear transducers.
- Sensing the presence of the magnetic field in industrial applications.
- Used in smartphone to check whether the flip cover accessory is closed.
- For contactless measurement of DC in current transformers, a Hall Effect sensor is used.
- This is used as a sensor to detect the fuel levels in automobiles.
Examples
- Some of the examples for the application of Hall Effect sensors are the current transformers, Position sensing, Galaxy S4 Accessories, Keyboard switches, computers, Proximity sensing, speed detection, current sensing applications, tachometers, anti-lock braking systems, magnetometers, DC motors, disk drives, etc.