# How to determine the error of the instrument

Implementation of many educational and research work connected with carrying out a wide variety of measurement of physical quantities. After receiving the results of the measurement instrument is usually followed by their processing. For an exact match of the results of calculations required to take into account the experimental picture allowable measurement error. Determination of instrumentation errors is carried out by special techniques.

## Instruction how to define a device error

Step 1:

Use this to determine the absolute instrumental error, depending on device characteristics, special means of measurement error of the table. For example, for drawing lines up to 500 mm in length and 1 mm scale division of absolute instrumental error is plus or minus 1 mm; and a micrometer for measuring range of 25 mm to 0.01 mm and the price, this value will be plus or minus 0.005 mm.

Step 2:

Determine the absolute error count. It is obtained from the not very accurate readings, measured using measuring devices and appliances. In most cases, this value is equal to half the price of the instrument scale division. When measuring the error of the absolute time frame take the same price division stopwatch (hours).

Step 3:

Calculate the maximum absolute error of direct observation. It is defined as the result of adding the absolute instrumental error and absolute error count (if other types of errors can be ignored): A '= Au + Ao where A' - the maximum absolute error of direct observation; Au - absolute instrumental error; Ao - absolute error count.

Step 4:

In determining the absolute error of the measurement device round it to one significant figure. The numerical value of the result of the measuring procedure is rounded so that the latter figure it was at the same rank as the figure error.

Step 5:

If there is a need for instrument re measurements made under identical controlled conditions, then the error is called a random, define as the arithmetic average of all results of error measurement.

Step 6:

To determine the absolute instrumental error of electrical measuring instruments, check its accuracy class. It is usually indicated on the scale of the device or in the data sheet (description).