Class 12PhysicsMoving Charges and MagnetismThe Moving Coil Galvanometer (Sensitivity) and Ammeter and Voltmeter Conversion
EasyWhy should the resistance of an ammeter be as low as possible?
(N/A) An ammeter is connected in series with the component to measure the current flowing through it.
If the resistance of the ammeter is $R_{1}$ and the resistance of the circuit is $R$,then after connecting the ammeter,the total resistance of the circuit becomes $R + R_{1}$.
Consequently,the measured value of the current,$I = \frac{V}{R + R_{1}}$,will be less than the true value of the current that would flow in the absence of the ammeter $(I_{true} = \frac{V}{R})$.
To minimize this error and ensure that the ammeter measures the true value of the current,the resistance of the ammeter $(R_{1})$ should be as low as possible,ideally approaching zero.
If the resistance of the ammeter is $R_{1}$ and the resistance of the circuit is $R$,then after connecting the ammeter,the total resistance of the circuit becomes $R + R_{1}$.
Consequently,the measured value of the current,$I = \frac{V}{R + R_{1}}$,will be less than the true value of the current that would flow in the absence of the ammeter $(I_{true} = \frac{V}{R})$.
To minimize this error and ensure that the ammeter measures the true value of the current,the resistance of the ammeter $(R_{1})$ should be as low as possible,ideally approaching zero.
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