2.1 INTRODUCTION

Hans Oersted's discovered the relationship between current and magnetism in 1820. His discovery can be found in basic meter movement in galvanometer that used in DC measurements.

Moving coil in galvanometer was patented by Jacques d’ Arsonval in 1881. The movement of meter that we use today is just the same basic developed by Jacques d’ Arsonval.

Hence, permanent magnet-moving coil (PMMC) meter movement named as d’ Arsonval meter movement.