Question

A galvanometer has a resistance of 25 Ω and its full scale deflection current is 25 μA. What resistance should be added to it to have a range of 0-10 V?

Answer 1

Given G = 25 μA.

Maximum voltage to be measured is V = 10 V.

The galvanometer resistance G = 25 Ω.

The resistance to be added in series,

X = `"V"/"I"_"g" - "G"`

= `10/(25 xx 10^-6) - 25`

= 399.975 × 10³ Ω