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Calibration is needed due to
To find accuracy
To find error
To find class
All of above
All of above
Quick Summary: Calibration is the quantitative process of comparing the output of an instrument against a known standard or reference to determine its performance characteristics. This process helps identify deviation (error), verify the instrument's accuracy, and confirm its class (precision/accuracy grade) relative to international standards.
Calibration is the quantitative process of comparing the output of an instrument against a known standard or reference to determine its performance characteristics. This process helps identify deviation (error), verify the instrument's accuracy, and confirm its class (precision/accuracy grade) relative to international standards.
Absolute Error=Am−At
Relative Error=AtAm−At×100%
Accuracy=1−∣Relative Error∣
Calibration works by applying a known input Istd from a primary or secondary standard to the instrument under test and measuring its output Omeas. The difference between the measured value and the true value determines the absolute error e=Omeas−Istd. By performing this over the entire measuring range, one can establish the correction curve, verify the class index, and define the instrument's reliability.
Calibration ensures traceability to national or international standards.
Instrument class defines the maximum permissible error as a percentage of full-scale reading.
Regular calibration is necessary due to physical wear, aging of components, and environmental exposure.
Calibration provides a record of traceability for quality assurance audits.
Ensures measurement reliability and safety.
Maintains regulatory and industry compliance.
Can be time-consuming for high-precision equipment.
High cost associated with maintenance of standard references.
Electrical power meters (energy meters).
Pressure gauges and temperature sensors.
Industrial control systems in automation.
In electrical measurements, instruments are assigned a 'Class' (e.g., 0.5, 1.0) which specifies the error limit in terms of percentage of the full-scale deflection.
Option C refers to finding the 'Class', which is effectively determined during the calibration process to label the instrument's accuracy grade.
D is correct — Calibration encompasses the determination of absolute error, verification of accuracy, and assignment of the instrument class.
Always remember that accuracy is inversely related to error; hence, determining the error of an instrument is synonymous with quantifying its accuracy and precision grade.