The weighing has being existed for a long time. The first scale was invented 5000 BC and known as equal-arm balance. The other weighing method was spring scales. The principle of usage of that scales consisted in display of weight by attached to spring pointer. The advantage of such scales is that they do not require any standard mass after calibration. As to repeatability and reliability, it is important to select the spring material appropriately and set the spring sufficiently that the indicator would show correctly.

In our work we use another method for weighing. It is load cell. It is the best converter to display the weight on screen.

The way of work of the load cell based on weighing indicators is technically similar to the way of work of the spring scales, in spite of unlikeness of the components used for spring. For spring scales this component is made from steel and aluminium. As to load cells strain gage is used. This strain gage has an electronic structure, that can be in various sizes and shapes. It is utilized to analyze the static and/or dynamic resistance of system or some detached structure. In commercial load cells strain gage has 4 or 5 variety of size and shape (strain gages that are specially produced for analysis of various composites as marble, ceramic, glass, concrete and etc. are out of our topic)

In general Load Cell is a detached structure, whereas in weighing is a static measurement. As it used in weighing it works on just a single axis. (Force of gravity exists due to acceleration of world mass and varies in depending on where you are.) Another name for the load cell is converter of force. Force is equal to mass multiplied by acceleration. Weight is the product of the mass of the object and magnitude of gravitation of acceleration.