The first galvanometer was assembled by German mathematician and physicist Johann Schweigger, who called it a multiplier.
A galvanometer consists of a coil mounted so that it’s allowed to pivot freely within a magnetic field created by the poles of one or more permanent magnets. A needle is attached to the coil.
When electricity is allowed to pass through the coil, the magnetic field generated by the current-carrying wire interacts with the field of the permanent magnets, generating torque that rotates the coil. The deflection of the galvanometer’s needle is proportional to the current flowing through the coil. Here, we show you the concept of those interacting magnetic fields.