Calibration is the objectives of determining the accuracy of an instrument or measurement system by comparing its readings with those of a known, standard reference. If any deviation is observed, adjustments are made to ensure the instrument provides accurate and reliable measurements.


The main purposes of calibration are:

1. Accuracy: To ensure the instrument gives correct measurements.

2. Reliability: To maintain consistent readings over time.

3. Error Detection: To identify any deviations or faults in the instrument.
   
   

where,
T = Test value
S = Standard value

Calibration of voltmeter :

Calibration of Voltmeter is the process of checking the accuracy of the reading of the Voltmeter under test (V_t) by comparing it with the standard Voltmeter (V_s) one. In other words, calibration checks the correctness of the instrument by comparing it with the reference standard.

where,
V_t = Test value
V_s = Standard value


Figure 1.0 Calibration of an AC voltmeter

Calibration of ammeter :

Calibration of Ammeter is the process of checking the accuracy of the reading of the ammeter under test (A_t) by comparing it with the standard Ammeter (A_s) one. In other words, calibration checks the correctness of the instrument by comparing it with the reference standard.


where,
A_t = Test value
A_s = Standard value


Figure 1.1 Calibration of an AC ammeter