Measuring Instruments

Measuring Instruments

Measuring Instrument a device use to find the value of quantity or variable known as measuring instruments.

What is electrical Measuring Instrument?

Electrical measuring instruments are that instrument which is use too find electrical quantities. In which are current, voltage, resistance, power frequency, power factor, etc. are involve.

Classification of electrical instruments:

 Moreover, Electrical instruments can be classify into two major categories

  1. Absolute Instruments: Absolute instrument is that instruments which give the value of the quantity to be measured in terms of the constant of the instruments and their deflection.

These instruments also did not require the calibration .Moreover, In Such instruments they did not show the accurate value.

Moreover, For the accurate value you have to multiply it with some constants. Such as Tangent galvanometer.

Moreover, It is very difficult to get the reading from such meter and can cause time consumption. therefore, They are use in laboratories, institutions etc.

  • Secondary Instruments:  Thus the instruments that indicate the value of electrical quantity toe measure directly from the deflection of the pointer of the instrument or on the screen of the meter are secondary instruments.

The secondary instruments are calibrate with absolute instruments. when they are calibrate so they are able to show the reading directly on the screen. Therefore, the reading in such instruments is easy to determine. Also these instruments are widely used in schools, Collages, powerhouses and grid stations etc. Thus an Example of secondary instruments are Voltmeter, Ampere meter, Ohmmeter etc.

Difference between Absolute and Secondary Measuring Instruments

Therefore, Below are the few differences between absolute and secondary instruments.

Absolute InstrumentsSecondary Instruments
Firstly, they do not need any calibration. in such instruments calibration is require for the correct reading
Secondly, They cannot show the value directly you have to multiply with some constantsSecondly, They show reading directly on the screen
In absolute instruments the Reading is 100% accurate.The reading is approximately accurate.
These instruments are use where accurate readings are required.These Instruments are require where accuracy is not important.
These instruments are very sensitive.These instruments are less sensitive.

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