Measurement of Resistance (Resistivity) by Simple DC Galvanometer

Measurement of Resistance (Resistivity) by Simple DC Galvanometer

• Galvanometer is first calibrated by use of standard resistance of the values 10 MΩ with tolerance ± 0.5 to ± 1 %.

Calculations

The resistance of the specimen (R_P) is given by R_P = V / D x G

Where

D = deflection in cm with specimen

G = Galvanometer sensitivity A / cm

G = (V/R_S) x 1/n 1/D_S

Here R_{S =} Standard resistance used for calibration

V = Supply voltage

D_{S =} Deflection in cm with standard resistance in position

n = The universal shunt ratio,

Volume resistivity P = π r²R/t

Where

t = thickness of specimen meter

R = Specimen resistance

r = radius of electrode

• The ideal will be cleared by taking actual observations of the experiments in the following case.