A millivoltmeter of $25 \mathrm{mV}$ range is to be converted into an ammeter of 25 A range. The value (in…
A millivoltmeter of $25 \mathrm{mV}$ range is to be converted into an ammeter of 25 A range. The value (in ohm) of necessary shunt will be
0.001
0.01
1
0.05
Solution
The full scale deflection current
$i_g=\frac{25 \mathrm{mV}}{G} \text { ampere }$
where $G$ is the resistance of the meter.
The value of shunt required for converting it into ammeter of range $25 \mathrm{~A}$ is $S=\frac{i_g G}{i-i_g}$
So that, $S \approx \frac{25 \mathrm{mV}}{25}=0.001 \Omega$