Question

Explain principle and working of moving coil galvanometer with diagram ?

Answer 1

First you need to know what is moving coil - galvanometer ??? Galvanometer is operated by the force exerted by an electric current flowing in a movable coil suspended in a magnetic field.................. !!!!Working of moving coil of galvanometer :- Principle: - Its working is based on the fact that when a current carrying coil is placed in a magnetic field, it experiences a torque. Principle: Its working is based on the fact that when a current carrying coil is placed in a magnetic field, it experiences a torque. Working: Suppose the coil PQRS is suspended freely in the magnetic field. Let l = Length PQ or RS of the coil b = Breadth QR or SP of the coil n = Number of turns in the coil Area of each turn of the coil, A = l × b Let B = Strength of the magnetic field in which coil is suspended I = Current passing through the coil in the direction PQRS Let, at any instant, α be the angle which the normal drawn on the plane of the coil makes with the direction of magnetic field. The rectangular coil carrying current when placed in the magnetic field experiences a torque whose magnitude is given by, τ = nIBA sinα Due to deflecting torque, the coil rotates and suspension wire gets twisted. A restoring torque is set up in the suspension wire. Let θbe the twist produced in the phosphor bronze strip due to rotation of the coil and K be the restoring torque per unit twist of the phosphor bronze strip. Then, Total restoring torque produced = kθ In equilibrium position of the coil, Deflecting torque = Restoring torque ∴ NIBA = kθ. So this is the working moeel of galvanometer