voltmeter measures voltage across a known source of potential. This voltage measurement can be ac or dc voltage. In case of dc voltage measurement, another variety of the voltmeter is called as center zero voltmeter. The voltage referred on the scale of the voltmeter refers to full-scale deflection (fsd). The fsd indication is always on the right hand side of the instrument. It is necessary to study the name plate details of the voltmeter to identify the type of meter namely moving coil or moving iron type, in addition to fsd. The voltmeter under study is moving coil type ac voltmeter.
calibrating a voltmeter is a two step approach. A voltmeter is calibrated for
i. Accuracy of the basic meter or
(a) calibrate and display on the scale of the meter, for functional applications, like displaying a parameter with engineering units like rpm, kg/cm2 or 0c etc.
now there is a need to study how to accomplish the above-defined tasks. The scope of this instrument restricts to performing the above two tasks only.
this trainer has all the necessary facilities to carryout the experiment needed for calibration. This unit requires an external variac, which can be adjusted in the range of 0 to 230v ac.specifications:
voltmeter under study : moving coil type
range : 0 to 30 v ac
digital meter : 3-½ digit digital voltmeter
range : 0 to 230 v ac
potential divider : known values of resistors of 1% for calculating the voltage applied
across the device under test.
an external variac required. This is not in the scope of supply with basic experimental setup