(1) Moving Coil Galvanometer, Ammeter and Voltmeter
(a) Write the expression for the current sensitivity of a moving coil galvanometer.
The current sensitivity of a moving coil galvanometer is given by:
I_s = \frac{NAB}{C}
where
- $I_s$ is the current sensitivity in radians per ampere
- $N$ is the number of turns in the coil
- $A$ is the area of the coil in square meters
- $B$ is the magnetic field strength in teslas
- $C$ is the torsional constant of the suspension in newton-meters per radian
(b) A galvanometer has a resistance of 50 $\Omega$ and gives a full scale deflection for a current of 10 mA. How can it be converted into an ammeter of range 0 to 1 A?
To convert a galvanometer into an ammeter, we need to add a shunt resistor in parallel with the galvanometer. The shunt resistor should have a resistance such that the total current through the galvanometer and the shunt resistor is equal to the full scale current of the galvanometer. In
