Introduction

System description

A D’Arsonval galvanometer is a device designed to detect small currents in order of nA or µA. Its application lies in bridges (Wheatstone bridge, Kelvin double bridge etc.) and potentiometers, where it indicates null deflection or zero current. The working principle of the galvanometer is based on the equation $$\tau_d = \tau_r$$ Where τ_d is the deflecting torque and τ_d ∝ i_d (coil current)
τ_r is the restoring torque, brings the moving system (spring enabled) back to the initial position. The galvanometer pointer movement shown in Fig. 1, employs a spring-loaded coil through which the measured current flows.