Magnetic Effect:
I) In PMMC meters:
➢ When a current is passed through a conductor, magnetic field is produced round the conductor. Due to this field when current carrying conductor is placed in a magnetic field it experiences a mechanical force. Examples: PMMC, galvanometer
II) In Moving Iron Type meters:
➢ When we bring one permanent magnet near to another electromagnet then there is a force of attraction or repulsion depending on the direction of current in the coil of electromagnet. ➢ Examples: Moving iron type instruments, Moving coil type instruments
III) In Electrodynamic meters: When a current is passed through a conductor, magnetic field is produced round the conductor. Due to this field when current carrying conductor is placed in a magnetic field it experiences a mechanical force.
Examples: Electrodynamometer type instruments, Induction type instrument.