Voltage across shunt = Voltage across galvanometer [ I_g \cdot R_g = (I - I_g) \cdot S ] [ S = \fracI_g R_gI - I_g ]
Let ( V ) = voltage to be measured, ( I_g ) = full-scale deflection current. project file on moving coil galvanometer for class 12 pdf
Let ( I ) = total current to be measured, ( I_g ) = full-scale deflection current of galvanometer, ( R_g ) = galvanometer resistance. Voltage across shunt = Voltage across galvanometer [
To increase sensitivity, increase ( N ), ( B ), or ( A ), or decrease ( k ). 7. Conversion into Ammeter A galvanometer can measure only small currents (μA to mA range). To measure larger currents, a low resistance called a shunt (( S )) is connected in parallel with the galvanometer. Total resistance = ( R_g + R )
Total resistance = ( R_g + R ) By Ohm’s law: [ V = I_g (R_g + R) ] [ R = \fracVI_g - R_g ]
A low-range galvanometer becomes a high-range ammeter. 8. Conversion into Voltmeter To measure voltage, a high resistance (( R )) is connected in series with the galvanometer.