The Hall effect refers to the phenomenon that its magnitude is proportional to the vertical component of the magnetic induction and the magnitude of the current. When the current passes through the conductor in the magnetic field, a potential difference that is perpendicular to both the current direction and the magnetic field direction will be generated on the conductor, then, Let's take a look at the main applications of open-loop Hall current sensors!
According to the Hall effect, Hall elements, amplifier circuits, temperature compensation circuits and stabilized power supply circuits are generally integrated on one chip, and people use semiconductor materials to make Hall elements. Because the potential difference generated on the Hall element is small, it is called a Hall sensor.
It can be seen that the open-loop Hall current sensor is the integration of the Hall element based on the Hall effect and other complementary circuits. What is the main application of the Hall sensor?
1. Classification of Hall sensors
There are two types of Hall sensors: linear Hall sensors and switch Hall sensors.
1. Linear Hall sensor is composed of Hall element, linear amplifier and emitter follower, and outputs analog quantity. Hall sensors are mainly used for AC and DC current and voltage measurement. Hall sensors are available in open loop and closed loop. Closed-loop Hall sensors are also known as zero-flux Hall sensors.
2. The switch-type Hall sensor is composed of stabilizer, Hall element, differential amplifier, Smith trigger and output stage, and outputs digital quantity. Switch-type Hall sensors also have a special form called key-lock Hall sensors.
Second, the main application of open-loop Hall current sensor
Typical applications for open-loop Hall current sensors are current measurement and displacement measurement.
01. Current measurement
There is a magnetic field inside the energized solenoid, so a Hall sensor can be used to measure the magnetic field to determine the magnitude of the current in the wire. Its magnitude is proportional to the current in the wire.
Hall current sensors can measure current and voltage of arbitrary waveforms. Hall effect sensors generally aim at the disadvantage of large temperature drift, and the output terminal can truly reflect the waveform parameters of the current or voltage at the input terminal. To ensure the accuracy of measurement; it has the characteristics of high precision, easy installation and low price. The compensation circuit is used for control, which effectively reduces the influence of temperature on the measurement accuracy.
Hall current sensors are widely used in inverter devices, inverter devices, UPS power supplies, communication power supplies, welding machines, electric locomotives, substations, CNC machine tools, electroplating, computer monitoring, power grid monitoring and other facilities that require isolation and detection of current and voltage.
02. Voltage measurement
It is a sensor that uses the Hall effect to convert the voltage on the primary side into a measurable signal on the secondary side, that is, a Hall voltage sensor. The magnetic field generated by the primary side current is detected by the Hall element in the air gap through the magnetic collecting material, and the primary side voltage limits the current to 10mA through the external or built-in resistance. After the current passes through the multi-turn winding, the corresponding electromotive force is induced. , its electromotive force is adjusted by the circuit and fed back to the compensation coil. The magnetic flux generated by the compensation coil is equal to the magnetic flux generated by the primary side current (the measured voltage is generated by the current limiting resistor). In fact, the Hall voltage sensor uses a The same technology as the magnetically balanced closed loop Hall current sensor, the direction is reversed, thus keeping the magnetic flux at zero in the magnetic core. That is, a zero-flux Hall current sensor.
03. Displacement measurement
When a constant current flows through the Hall element, the Hall potential will be output in a direction perpendicular to the magnetic field and current. When the Hall element moves up and down in the gradient magnetic field, the output Hall potential v depends on the displacement x in the magnetic field. If the size of the Hall potential is measured, the static displacement of the Hall element can be known.
The Hall-type displacement sensor is mainly composed of a gradient magnetic field composed of two half-ring magnetic steels and a germanium material semiconductor Hall chip (sensor element) device located in the center of the magnetic field. In addition, it also includes a measurement circuit (bridge, differential amplifier, etc.) and a display section.
3. Main applications of open-loop Hall current sensor
Open-loop Hall current sensor is mainly used to measure rotational speed, rotational speed, wind speed, flow velocity, proximity switch, door closing notifier, alarm, automatic control circuit, etc.
Measure rotational speed or rotational speed
A magnetic steel is attached to the end of the circular plate of non-magnetic material, and a Hall sensor is placed at the end of the circular plate. After the circular plate rotates once, a pulse is output from the Hall sensor to detect the rotational speed (counter), as long as the frequency counter is put in, speed can be detected.
When open-loop Hall current sensors are regularly arranged at predetermined positions on the track, pulse signals can be measured from the measurement circuit when a permanent magnet mounted on a traveling vehicle passes through. According to the distribution of the pulse signal, the moving speed of the vehicle can be measured.
The above are the main applications of open-loop Hall current sensors. If you want to know more, please feel free to contact us!