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### Course: Class 12 Physics (India)>Unit 4

Lesson 14: Moving coil galvanometer

# Moving coil galvanometer working

A moving coil galvanometer works on the principle that a current-carrying coil placed in a magnetic field, experiences a torque. The coil springs along with the radial field ensure the deflection to be proportional to the strength of the current. Created by Mahesh Shenoy.

## Want to join the conversation?

• Now that there's a piece of soft iron there instead of a ring of current that creates a magnetic field, how is there torque opposing the two coils? How can the torque reach equilibrium? I'm really confused.
(1 vote)
• Firstly, there's only one coil in consideration here, and the opposing torque is provided by the spring. The torque reaches equilibrium because the restoring torque is directly proportional to the twist in the spring so the restoring torque will equal the torque on the coil and hence the pointer. So at a particular current value, the torques cancel out and show a constant deflection until the torque on the coil is either removed or changed.