Question

A galvanometer having a coil of resistance 20 Ω needs 20 mA current for full scale deflection. In order to pass a maximum current of 3A through the galvanometer, what resistance should be added and how ?

Answer 1

Hii Dear,

◆ Answer -

Rs = 0.1342 Ω

● Explanation -

# Given -

Ig = 20 mA = 0.02 A

Rg = 20 Ω

I = 3 A

# Solution -

Shunt resistance added to convert galvanometer to ammeter is calculated by -

Rs = Ig.Rg / (I-Ig)

Rs = 0.02 × 20 / (3 - 0.02)

Rs = 0.1342 Ω

Therefore, a shunt resistance of 0.1342 need to be connected parallel to the galvanometer.

Hope this is helpful...