Electronic scales are a type of weighing instrument. Weighing instruments are tools that use Hooke's law or the principle of lever equilibrium to measure the mass of objects. According to the structural principle, they can be divided into three categories: mechanical scales, electronic scales, and electromechanical combined scales. Electronic scales mainly consist of three parts: the weighing system (such as the weighing pan and body), the force transmission system (such as the lever force transmission system and sensors), and the display system (such as the scale dial and electronic display).
When an object is placed on the weighing pan, pressure is applied to the sensor, which undergoes elastic deformation, causing the impedance to change. At the same time, the excitation voltage also changes, outputting a changing analog signal. This signal is amplified by the amplification circuit and output to the analog-to-digital converter. It is then converted into a digital signal that is easy to process and output to the CPU for computation and control. The CPU outputs the results to the display according to the keyboard command and program until the results are displayed.
Electronic scales use integrated electronic weighing devices that combine modern sensor technology, electronic technology, and computer technology. They can meet and solve the "fast, accurate, continuous, and automated" weighing requirements of real life. They can effectively eliminate human errors and better meet the requirements of legal metrology management and industrial production process control.
In the late 19th century, with the development of industrial technology, there were many automatic scales for rapidly weighing bulk materials. In the 1960s, electronic scales with a weighing accuracy of 0.1% appeared in the United States and Western Europe. With the development of the electronic scale industry, many brands gradually entered the market, and electronic scales were used by more and more people. More and more electronic scale brands became familiar to humans.
Electronic scales are measuring instruments that are subject to mandatory verification by the state. Their qualified products have standards for verification division values e and subdivision values D and are protected by the National Metrology Act. According to the requirements, any electronic scales used as social public measurement standards, the highest measurement standards used by departments, enterprises, and institutions, and electronic scales used for trade settlement, safety protection, medical and health, and environmental monitoring must undergo metrological verification before use. Those that have not applied for metrological verification in accordance with regulations or are unqualified after verification are not allowed to be used.
Some people believe that the heavier the object weighed within the range of the electronic scale, the greater the damage to the balance. This perception is not entirely correct. The maximum safe load of a general balance is the maximum static load it can withstand without permanently changing its measuring performance. Since electronic scales use electromagnetic force automatic compensation circuit principle, when the weighing pan is loaded (note that it should not exceed the weighing range), the electromagnetic force will push the weighing pan back to its original balance position, balancing the electromagnetic force with the gravity of the weighed object. As long as the weighing is within the allowable range, the impact of the weighing size on the balance is small and will not affect the accuracy of the electronic scale due to long-term weighing.