Hall sensor three wire wiring
Hall sensors generally have 3 wires and 2 wires. 3-wire VCC, OUT, GND. 2-wire VCC, OUT
A Hall sensor is a magnetic field sensor made based on the Hall effect. The Hall coefficient measured through Hall effect experiments can determine important parameters such as the conductivity type, carrier concentration, and carrier mobility of semiconductor materials.
The Hall effect is a type of magneto electric effect, which was discovered by A.H. Hall (1855-1938) in 1879 while studying the conductive mechanism of metals. Later, it was discovered that semiconductors, conductive fluids, and other materials also have this effect, and the Hall effect of semiconductors is much stronger than that of metals. Various Hall elements made using this phenomenon are widely used in industrial automation technology, detection technology, and information processing. The Hall effect is a fundamental method for studying the properties of semiconductor materials.
According to the principle of the Hall effect, the magnitude of the Hall potential depends on Rh being the Hall constant, which is related to the semiconductor material; I is the bias current of the Hall element; B is the magnetic field strength; D is the thickness of the semiconductor material. For a given Hall device, when the bias current I is fixed, UH will depend entirely on the measured magnetic field strength B.
A Hall element generally has four output terminals, two of which are the input terminals of the bias current I of the Hall element, and the other two are the output terminals of the Hall voltage. If the two output terminals form an external circuit, Hall current will be generated. Generally speaking, the setting of bias current is usually provided by an external reference voltage source; If high precision is required, the reference voltage source should be replaced with a constant current source. In order to achieve high sensitivity, some Hall elements have coated alloys with high magnetic permeability on their sensing surfaces; This type of sensor has a high Hall potential, but saturates at around 0.05T and is only suitable for use in low limit and small range applications.
By controlling the current I at both ends of a semiconductor wafer and applying a uniform magnetic field with a magnetic induction intensity of B in the vertical direction of the wafer, a Hall voltage with a potential difference of UH will be generated in the direction perpendicular to the current and magnetic field.
Hall sensors are divided into two types: linear Hall sensors and switch type Hall sensors.
（1） A switch type Hall sensor consists of a voltage regulator, Hall element, differential amplifier, Schmitt trigger, and output stage, which outputs digital signals. There is a special form of switch type Hall sensor called lock key type Hall sensor.
（2） A linear Hall sensor consists of Hall elements, linear amplifiers, and emitter followers, and outputs analog signals.
Linear Hall sensors can be divided into open-loop and closed-loop types. Closed loop Hall sensor, also known as zero flux Hall sensor. Linear Hall sensors are mainly used for measuring AC/DC current and voltage.
1. Hall sensors can measure current and voltage of any waveform, such as DC, AC, pulse waveform, etc., and even measure transient peak values. The secondary current faithfully reflects the waveform of the primary current. However, ordinary transformers are incomparable and are generally only suitable for measuring 50Hz sine waves;
2. There is good electrical isolation between the primary and secondary circuits, with an isolation voltage of up to 9600Vrms;
3. High accuracy: The accuracy is better than 1% within the working temperature range, which is suitable for measuring any waveform;
4. Good linearity: better than 0.1%;
5. Wide bandwidth: The rise time of high bandwidth current sensors can be less than 1 μ s; However, the bandwidth of the voltage sensor is relatively narrow, generally within 15kHz. The rise time of a 6400Vrms high-voltage voltage sensor is about 500uS, and the bandwidth is about 700Hz.
6. Measurement range: Hall sensors are a series of products, with current measurement up to 50KA and voltage measurement up to 6400V.
Hall current sensors are generally powered by dual power sources of 12-15V, with wiring consisting of: power supply+, power supply -, output+, output -. This is usually the case, but there are also three wire systems where the power supply and output - are grounded.
One positive pole of the power supply, one common point, and one signal output.
The Hall voltage varies with the strength of the magnetic field. The stronger the magnetic field, the higher the voltage, and the weaker the magnetic field, the lower the voltage. The Hall voltage value is very small, usually only a few millivolts, but it can be amplified by the amplifier in the integrated circuit to output a strong signal. If the Hall integrated circuit is used for sensing, mechanical methods are required to change the magnetic field strength.
The method shown in the figure is to use a rotating impeller as a switch to control the magnetic flux. When the impeller blades are in the air gap between the magnet and the Hall integrated circuit, the magnetic field deviates from the integrated chip and the Hall voltage disappears. In this way, the change in output voltage of the Hall integrated circuit can indicate a certain position of the impeller drive shaft. Using this working principle, the Hall integrated circuit chip can be used as an ignition timing sensor.Hall Effect Sensor Belonging to passive sensors, it requires an external power source to operate, which enables it to detect low-speed operating conditions.