Labo Élec
electrical lab simulator
Exercise from the chapter "Measurement & instruments"
Level 4 of 5 · Skills: Calculate
An ammeter with internal resistance r_A = 2 Ω reads full scale at i = 0.01 A. We want to measure up to I = 5 A. Compute the resistance of the shunt to place in parallel.
rA = 2 Ω · i = 0.01 A · I = 5 A
Parametric exercise: the values change with every draw; these are one example.
Guided problem in 4 steps: unknown, formula, units, data, result.
Same voltage across the meter and the shunt: r_A·i = R_s·(I − i) → R_s = 2 × 0.01 / (5 − 0.01) = 4.01 mΩ.