Definition of Measurement and Calibration

 Definition of Measurement and Calibration


Definition of Measurement and Calibration
Measurement and Calibration


Measurement:


Measurement of a given quantity is the act or result of a quantitative comparison between an unknown quantity and a predefined standard quantity
e.g.for measuring the weight of a quantity, the standard taken is 1 kg.

Measurement  using an instrument as a physical means of determining a quantity or variable.

Instrument:


Define an instrument:
Instrument can be defined as a device for measuring the value or magnitude of a quantity or variable.

The electronic instrument is based on electrical or electronic principles for their
measurement.

Calibration:


What do you mean by calibration?

 Calibration is a process of estimating
the value of a quantity by comparing that quantity with given standard quantity.

The standard with which comparison is made is called as standard instrument.

The unknown quantity is to be calibrated.This quantity is called as test
quantity. If an instrument is to be calibrated,it is called as test instrument.

For calibration,the test instrument will be compared with the standard instrument.

The calibration offers a guarantee to the device or the instrument that it is operating Witn required accuracy, under the stipulated environmental conditions.

Calibration creates the confidence of using properly calibrated instrument in the user's mind.

It is essential to calibrate an instrument from time to time.

The calibration process deals with visual inspection of defects, zero adjustment etc.

By applying known values of quantities to be measured and recording the corresponding output,the calibration characteristics of an instrument can be determined.The output values are compared with the input values to estimate the error in measurement.Such a record obtained from calibration is called as calibration record.

The calibration record is recorded in tabular form or in graphical form.If it is recorded in graphical form it is called as a calibration curve.Such a calibration record is useful to obtain the characteristics of an instrument.

Steps for Calibration:


The following step is necessary for Calibration

1. Examine the instrument construction and identify all the possible input.

2.Make a decision about the appropriate input required for Calibrating the instrument.

3.Procure apparatus that will allow user to vary the input over the rang. Procure the standards to measure each input.

4.Make some of the input constant and vary the other and record the output and develop the desired static input-output relations.




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