What are Measuring Instruments?

The devise that is used for measurement of certain physical quantity is called as measuring instrument. The measuring instruments are used frequently in our day-to-day life for the measurement of various quantities like length, weight, temperature, pressure, current, voltage etc. The instruments indicate the value of these quantities, based on which we get some understanding and also take appropriate actions and decisions.

There are two main types of the measuring instruments: analogue and digital. The analogue instruments indicate the magnitude of the quantity in the form of the pointer movement. One has to learn reading such instruments since there are certain markings on the scale. They usually indicate the values in the whole numbers, though one can get the readings up to one or two decimal places also. The readings taken in decimals places may not always be entirely correct, since some human error is always involved in reading.

The digital measuring instruments indicate the values of the quantity in digital format that is in numbers, which can be read easily. One doesn't needs any prior training to read these instruments since they indicate the values directly in the numerical form. They can give the readings in one or more decimal places. Since there is no human error involved in reading these instruments, they are more accurate than the analogue measuring instruments.

Most of the measuring instruments indicate the value of parameter in the form of the indicator movement, which gives us the magnitude of that quantity. There are many other functions performed by the instruments as indicated below:

1) Indicating the value of the physical quantity: The instruments are calibrated against the standard values of the physical quantities. The movement of the pointer directly indicates the magnitude of the quantity, which can be whole numbers or also fractions. Nowadays, the digital instruments are becoming very popular, which indicate the values directly in numerical form and even in decimals thus making them easy to read and more accurate.

2) Measuring instruments used as the controllers: There are number of instruments that can be used as the controllers. For instance, when a certain value of the pressure is reached, the measuring instrument breaks the electrical circuit, which stops the running of compressor. Similarly, the thermostat starts or stops the compressor of the refrigeration system depending on the temperature achieved in the evaporator.

3) Recording the data: Some measuring instruments can also be used to record and also store the data. In this age of computerization storing the recorded data has become quite easy. There are number of instruments that are connected to the pen that moves on the paper. As the pointer of the instrument moves as per the changes in the magnitude of the quantity, the pen also moves on the paper making the graph against certain parameter like time. Attaching small memory to the PCB can also enable recording of the instruments in the chip.

4) Transmitting the data: The measuring instruments can also be used to transfer the data to some distant places. The instruments kept in unsafe locations like high temperature can be connected by wires and their output can be taken at some distant places which are safe for the human beings. The signal obtained from these instruments can also be used for operating some controls.

5) Do calculations: Some measuring instruments can also carry out a number of calculations like addition, subtraction, multiplication, division, etc. Some can also be used to find solutions to highly complex equations.