The Hall effect working mechanism of vacuum pressure switches

The working mechanism of vacuum pressure switches that utilize the Hall effect to achieve pressure sensing and signal conversion is as follows:

The basis of the Hall effect

The Hall effect refers to the phenomenon where when current passes through a semiconductor perpendicularly to an external magnetic field, the carriers are deflected, generating an additional electric field in a direction perpendicular to both the current and the magnetic field, thereby creating a potential difference at both ends of the semiconductor. The potential difference between the two ends is called Hall potential, and its expression is U=K

cdotI

cdotB/d, where K is the Hall coefficient, I is the current passing through the thin sheet, B is the magnetic induction intensity of the applied magnetic field, and d is the thickness of the thin sheet. It can be seen from this that the sensitivity of the Hall effect is directly proportional to the magnetic induction intensity of the applied magnetic field.

The role of Hall elements in vacuum pressure switches

In the vacuum pressure switch, the Hall element, as the core sensitive component, its working state is directly related to the change of the magnetic field. When the pressure of the vacuum system changes, it will be transformed into a change in magnetic field intensity through mechanical structure. For instance, some vacuum pressure switches employ magnetic pistons or diaphragm structures. Changes in pressure cause the magnetic components to shift, thereby altering the magnetic field strength at the position where the Hall element is located.

Signal conversion process

Magnetic field sensing: The Hall element senses the changes in magnetic field intensity in real time. When the magnetic field intensity exceeds the preset threshold, the carriers inside the element are deflected under the Lorentz force, generating a Hall potential difference in the direction perpendicular to the current and the magnetic field.

Electrical signal processing: The weak voltage signal output by the Hall element is processed by the amplification circuit and then sent to the comparator for comparison with the preset reference voltage. If the input voltage exceeds the reference voltage, the comparator outputs a high level. Conversely, a low level will be output.

Status output: The level signal output by the comparator drives the switching device (such as a transistor) to conduct or cut off, ultimately forming a switching signal output. For instance, when the vacuum pressure reaches the set value, the Hall element detects the change in the magnetic field and triggers the switch to act, outgenerating an electrical signal to control the related equipment.

The advantages of Hall effect vacuum pressure switches

Non-contact measurement: Hall elements achieve pressure detection by sensing changes in the magnetic field, avoiding the wear problem of mechanical contacts and significantly extending the service life of the equipment.

Fast response speed: Changes in the magnetic field can be instantly sensed by Hall elements, and in combination with a fast signal processing circuit, a millisecond-level response speed can be achieved.

Strong anti-interference ability: The Hall element with a sealed packaging structure can effectively resist environmental interference such as dust and oil stains, ensuring stable operation under harsh working conditions.