A galvanometer has an internal resistance of 200 Ω and requires a current of 5.0 mA for full-scale deflection. What resistance should be connected in parallel with this galvanometer to make an ammeter that reads 10 A at full-scale deflection?

Question

Quizplus · Accepted Answer

To convert the galvanometer to an ammeter that reads 10 A at full-scale deflection, a shunt resistor (R_s) is connected in parallel. The current through the galvanometer is 5.0 mA, so the remaining current (10 A - 5.0 mA) must pass through the shunt. Using the formula R_s = (R_g * I_g) / (I - I_g), where R_g = 200 Ω, I_g = 5.0 mA, and I = 10 A, we find R_s = 0.10 Ω.

A Galvanometer Has an Internal Resistance of 200 Ω and Requires