In modern times, a weighing instrument is a device that uses Hooke's law or the principle of lever balance of force to measure the mass of an object. It generally consists of a load-bearing system, a force transmission conversion system and an indication system. According to the structural principle, it can be divided into three types: mechanical scale, electronic scale, and electromechanical combined scale.

    Mechanical scales are generally divided into steel scales and spring scales. A steelyard scale is an equal-arm lever, a simple weighing instrument that uses the principle of leverage to weigh items. It generally consists of a weighing rod, a metal weighing hammer, and a rope. A spring balance, also known as a spring dynamometer, is a device that measures the force by using the relationship between the deformation of the spring and the external force. At different latitudes of the earth, the mass of the same object measured by the same spring balance will vary.

    The electronic scale is an automatic weighing equipment for weighing goods. It is through the power-to-electricity conversion of the sensor and the signal collected by the weighing instrument to complete the weighing of the goods. Its working principle is: through the gravity sensor, the force signal is converted into a voltage or current signal, and then converted into a digital signal by an A/D (digital-to-analog conversion) processor. numerical value.

    The electromechanical combined scale is a weighing instrument that combines a mechanical scale and an electronic scale. It is the main weighing equipment used in the measurement of bulk goods such as chemicals, logistics, ports, factories and mines.