When current is passed throgh a galvanometer, the coiloscillates about its mean position before it comes to rest.To bring the coil to rest immediately, the coil is wound on ametallic frame.Now, when the coil oscillate, eddy currents are set up in themetallic frame, which opposes further oscillations of the coil.This inturn enables the coil to attain its equilibrium positionalmost instantly.Since the oscillation of the coil die out instantaneously, thegalvanometer is called dead beat galvanometer.