The working principle of a weighing sensor is to convert the weight signal of an object into a measurable electrical signal output. Its core is based on the physical process of "elastic body deformation-strain gauge resistance change-Wheatstone bridge voltage output."
When an object is placed on the weighing sensor, gravity causes a slight deformation of the elastic body inside the sensor. Strain gauges (a type of resistive element) are attached to the surface of the elastic body. The deformation causes a change in the resistance value of the strain gauges. These strain gauges are usually connected in a Wheatstone bridge circuit. When there is no load, the bridge is balanced, and the output voltage is zero. When weight is applied, the bridge becomes unbalanced, generating a weak voltage signal proportional to the weight.
This signal is amplified by an amplifier and then converted into a digital signal by an analog-to-digital converter (A/D). Finally, it is processed by a weighing instrument or microprocessor and displayed as a specific weight value.
Currently, the mainstream types of weighing sensors include:
Resistance strain gauge type: The most widely used, with high accuracy and simple structure, suitable for most static and dynamic weighing scenarios.
Piezoelectric: Utilizes the piezoelectric effect of quartz or ceramics, suitable for high-speed dynamic weighing, such as assembly line inspection.
Capacitive: Changes the capacitance value by varying the distance between the plates, offering advantages such as low power consumption and high dynamic response.
Digital: Integrates an A/D conversion module and microprocessor into the traditional strain gauge system, supporting remote transmission, automatic compensation, and anti-cheating functions, widely used in intelligent weighbridge systems.