A galvanometer has a resistance of $15\ \Omega$ and shows full scale deflection for a current of 4 m

Question

A galvanometer has a resistance of $15\ \Omega$ and shows full scale deflection for a current of 4 mA. How will you convert it into an ammeter of range 0 to 6 A?

Professor PC Thomas Classes · Answer

$S = \frac{I_g G}{I - I_g} = \frac{4 	imes 10^{-3} 	imes 15}{6 - 0.004} = \frac{0.06}{5.996} \approx 0.01\ \Omega = 10	ext{ m}\Omega$.