Balances are instruments whose purpose is to measure masses of bodies in greater or lesser quantity. They are characterized by their accuracy, their precision and their sensitivity. The first quality refers to the property that any physical instrument possesses to supply the result of a measurement with a value coinciding with the true one; this implies that the error is as small as possible. The term accuracy is often taken to mean precision. Sensitivity is determined by the ability to accurately determine results for very small values, and can be expressed as the difference between extreme values of several measurements of the same magnitude.
It is a laboratory instrument used to measure small masses. The saucers with which it is measured are located in a transparent box, which has doors. This is in order that dust and air do not affect the measurements. It is used mainly in laboratories.
Thus, for their correct use, they are used on a rigid, level table, with a single entrance, with a minimum amount of sunlight. They can be digital or mechanical. It delivers very precise measurements, since they use an electronic system that works with hundredths. Its use is necessary in laboratories, for example, in the case of weighing ingredients for the manufacture of substances or medicines. In order for their operation to be correct, they must be calibrated before use. Its working range is a few grams and with a resolution of up to 0.1 µg.
Precision electronic balances
A precision electronic balance is an instrument that is used to weigh through the intervention of gravity in order to determine a mass in question. Use a plate where the object to be measured is placed. Then the load cell is the one that allows to measure the weight exerted by the mass to be determined. Precision balances are used in laboratories and are practically essential for all tasks carried out there.
The resolution of these balances varies according to the model, the same happens with the working range. They generally have a resolution that can reach 0.01 g of resolution.
What is the principle of electromagnetic force compensation?
Precision electronic balances, analytical balances, and high-precision category microbalances work with a sensor based on electromagnetic force compensation. A coil on a loose moving shaft is inserted into a permanent magnetic field. The current from an optical electronic sensor maintains its position, controlled with a precision of better than one thousandth of a millimeter. The sensor records changes in the vertical position when the platter is loaded, which is used to change the coil current so that it can return to its initial position. The more weight added to the platter, the more current is required to compensate for it, which is shown as digits on the display.
As you can check the differences between a precision balance and an analytical balance they are very important, so you have to take them into account when deciding whether you need one or the other.