Moving-coil galvanometer 2026-10-14
View more
A moving-coil galvanometer has a winding that rotates about an axis, a restoring spring, and a pointer or optical readout. In the radial-field construction, a cylindrical iron core and shaped magnetic poles keep the magnetic field approximately in the coil's plane as it turns. The resulting moving-coil galvanometer torque is nearly independent of the deflection angle; the spring then converts electric current into a proportional settled deflection. [ref]
Figure 1.
Radial gap field and the force couple on a moving coil
. Original top-view schematic: the active wire lengths run perpendicular to the page. Dots indicate outward conventional current, crosses inward conventional current. Blue arrows show the local magnetic field; red arrows show the magnetic force on a current-carrying wire. Their force couple turns the coil counterclockwise for the illustrated positive electric current; the spring supplies the opposite torque. Only the working gaps are shown, not the complete magnetic field lines. Source. Details.
Read the full article