www.physicsbeckons.wordpress.com physicswithikgogia Page 1 MAGNETIC EFFECTS OF CURRENT MOVING COIL GALVANOMETER: It is a device used to detect/measure weak electric currents. Principle : A current carrying coil placed in a magnetic field experiences a torque. The magnitude of torque depends on the strength of the current. Construction: The essential parts of a moving coil galvanometer are as shown. It consists of a coil having a number of turns of a fine insulated copper wire wound over a soft iron core(shown cylindrical). The coil is held between the pole pieces of a powerful magnet N S and is pivoted to rotate in the field. The pole pieces are made cylindrical to ensure radial field. Two light springs are connected to the coil provide the restoring torque. A pointer moving on a scale is used to measure the current. Working: When current is passed through the coil, the magnetic field exerts a torque which tends to deflect the coil. As a result, the springs get twisted resulting in a restoring torque which increases with increase in deflection. The coil comes to rest when the restoring torque becomes equal to the deflecting torque. As the magnetic field is radial, therefore the plane of the coil is always parallel to the field.
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MAGNETIC EFFECTS OF CURRENT
MOVING COIL GALVANOMETER: It is a device used to detect/measure weak electric currents. Principle : A current carrying coil placed in a magnetic field experiences a torque. The magnitude of torque depends on the strength of the current. Construction: The essential parts of a moving coil galvanometer are as shown. It consists of a coil having a number of turns of a fine insulated copper wire wound over a soft iron core(shown cylindrical). The coil is held between the pole pieces of a powerful magnet N S and is pivoted to rotate in the field. The pole pieces are made cylindrical to ensure radial field. Two light springs are connected to the coil provide the restoring torque. A pointer moving on a scale is used to measure the current.
Working: When current is passed through the coil, the magnetic field exerts a torque which tends to deflect the coil. As a result, the springs get twisted resulting in a restoring torque which increases with increase in deflection. The coil comes to rest when the restoring torque becomes equal to the deflecting torque. As the magnetic field is radial, therefore the plane of the coil is always parallel to the field.
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Role of radial field:
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CONVERSION OF GALVANOMETER TO AMMETER AND VOLTMETER
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