Precision scales are used to weigh the mass of objects, while electronic scales typically use strain sensors, capacitive sensors, and electromagnetic balance sensors. Strain sensors have a simple structure and low cost, but their accuracy is limited. Electronic balance refers to a balance that uses electromagnetic force to balance the weight of an object being weighed. Its characteristics include accurate and reliable weighing, fast and clear display, automatic detection system, simple automatic calibration device, and overload protection device.

Precision scales usually have overload protection function, and when the weighed object is placed on the electronic balance, the pressure will be transmitted to the electronic balance sensor. At this point, the sensor deforms, resulting in a change in impedance and a simultaneous change in excitation voltage, outputting a changing analog signal. The signal is amplified and output to the analog-to-digital converter through an amplification circuit. The analog-to-digital converter converts it into a convenient digital signal and outputs it to the CPU for operational control. The CPU outputs the result to the display based on keyboard commands and programs. Before displaying the results, if the weight exceeds a certain amount, the sensor will no longer be pressed and the weight will not be displayed.

The weighing range of precision balance pressure sensors, if the pressure of the electronic balance is too high, it will damage the sensor of the electronic balance, making the measurement results of the electronic balance inaccurate or even damaging the electronic balance. Therefore, in simple terms, overload protection of the balance means that there is a device inside the electronic balance that can prevent the sensor from being subjected to pressure when the pressure on the electronic balance is too high, and make other components withstand pressure, effectively protecting the electronic device.