What principle does the weighing sensor use?

What principle does the weighing sensor use?

Accurate measurement of object weight is crucial in modern industries, logistics, healthcare, and scientific research. The weighing sensor, as a key device to achieve this goal, relies on complex and sophisticated principles behind it. This article will delve into the core principles of weighing sensors and reveal how they convert the weight of objects into quantifiable electrical signals.

The working principle of a weighing sensor is mainly based on the strain effect, which is a physical phenomenon that describes the internal deformation of a material when it is subjected to external forces, leading to a change in resistance value. Specifically for weighing sensors, their core components are elastic bodies made of highly elastic materials such as metal foil or strain gauges. When an external force (i.e. the weight of an object) acts on the sensor, the elastic body will undergo deformation, which will be converted into a change in resistance value according to a specific proportional relationship.

In weighing sensors, strain effects are cleverly utilized to detect the weight of objects. When an elastic body is subjected to external forces, its length increases and its cross-sectional area decreases, resulting in an increase in resistance. This change is called the positive strain effect. On the contrary, if an elastic body is subjected to compressive force, its length will shorten, its cross-sectional area will increase, and its resistance value will decrease, which is called negative strain effect. Whether it is positive or negative strain, the resistance change of an elastic body is proportional to the external force it experiences.

In order to convert these small resistance changes into easily measurable electrical signals, weighing sensors typically use Wheatstone bridge circuits. The Wheatstone bridge is a classic electrical measurement circuit consisting of four resistors, two of which are fixed, while the other two resistors (i.e. strain gauges) change with the deformation of the elastic body. When the elastic body undergoes deformation, the resistance value of the strain gauge will change, causing the bridge to lose balance and generate an output voltage. This output voltage is directly proportional to the degree of deformation of the elastic body (i.e. the weight of the object), and can therefore be used to quantify the weight of the object.

The voltage signal output from the Wheatstone bridge is usually very weak and may be affected by various noises. Therefore, in the circuit design of the weighing sensor, it is also necessary to include a signal conditioning circuit for amplifying, filtering, and linearizing the output signal. The amplification circuit is used to increase the strength of the signal, the filtering circuit is used to remove noise interference, and the linearization circuit is used to correct the nonlinear relationship between the output signal and the weight of the object to ensure measurement accuracy.

Weighing sensors are widely used in various situations where object weight needs to be measured due to their advantages of high precision, high sensitivity, fast response, and durability. In industrial automation, weighing sensors are used in material handling, production line monitoring, and quality control; In logistics transportation, they are used for load monitoring of trucks and containers; In the medical field, they are used for weight measurement and weight monitoring in medical devices. In addition, weighing sensors also play an important role in scientific research, aerospace and other fields.

The core principle of the weighing sensor is based on strain effect and Wheatstone bridge circuit. By converting the weight of an object into a change in resistance value, and then processing it through a signal conditioning circuit, an electrical signal proportional to the weight of the object is finally output. This principle not only provides high-precision and stable measurement capabilities for weighing sensors, but also has been widely applied and recognized in various fields. With the advancement of technology and continuous improvement of manufacturing processes, the performance of weighing sensors will be further enhanced, bringing more convenience and possibilities to human production and life