A $0-50 \mathrm{amp}$ ammeter has been guaranteed accuracy of $2 \%$ of full scale reading. The limi

Question

A $0-50 \mathrm{amp}$ ammeter has been guaranteed accuracy of $2 \%$ of full scale reading. The limiting % error when the metre is measuring 10 amperes is\

Professor PC Thomas Classes · Answer

Let I be the ammeter reading and $\Delta \mathrm{I}$ the error. Then $\%$ error $=\frac{\Delta \mathrm{I}}{\mathrm{I}} 	imes 100$ Case I : I=50 % Error = 2; $\Delta \mathrm{I}=$ ?\ $2=\frac{\Delta \mathrm{I}}{50} 	imes 100 \quad 	herefore \Delta \mathrm{I}=1$\ This is the minimum error that can be committed with the instrument what ever be the current.\ Case II : $\Delta \mathrm{I}=1 \mathrm{~A}, \mathrm{I}=10 \mathrm{~A}$ \ $\%$ error $=\frac{\Delta \mathrm{I}}{\mathrm{I}} 	imes 100=\frac{1}{10} 	imes 100=10 \%$\