The class of accuracy is one of the main characteristics of any measuring device. For each class there is a certain size of an admissible error. Any measurements are taken to obtain the most reliable data about physical data of an object. The measuring device has to correspond to an objective. At assessment of its quality it is necessary to consider several parameters including an accuracy class.
It is required to you
- - device;
- - standard documentation on the device.
Instruction
1. The class of accuracy of the device is usually specified on a scale. It is specified also in the instruction which is attached to the device. Look by what symbols he is designated. It can be capital Latin letters, the Roman or Arab figures. In the latter case any additional symbol is added.
2. If the class of accuracy is designated by Latin marking, it means that he is determined by an absolute error. The Arab figures without additional badges demonstrate that the given error is defining, at the same time the maximum or minimum value of possible measurement is considered. For example, the tick can be an additional badge. In this case also definition of a class goes on the given error, however on the basis of scale length. When determining a class on a relative error the Roman figures are affixed.
3. The device can not have any marking. It means that the error can make more than 4%, that is it is possible to use it only for very approximate measurements. In this case establish the size of an error. It is approximately equal to a half of the price of division. At the same time the result of measurement can be both more true on the error size, and it is less. Marking has to conform to state standards.
4. Calculate an error. The class of accuracy is defined as the attitude of any given error towards exact value. For example, absolute it is possible to present the differences between exact and approximate values in the form x and and, that is in the form of a formula s= (x-a) Relative is defined as the relation to the same difference to size and, and brought – to l scale length. Increase the received result by 100%.
5. There are eight classes of accuracy of arrow devices. They are determined by the given error. They are divided into precision and technical. The first are applied to exact measurements – for example, in laboratories. Range of errors at these classes – from 0.05 to 0.5. The devices belonging to the second category They can give an error from 1.0 to 4, 0. At the same time on all length of a scale a divergence between data of measurement and the actual value the same.