A device for indicating very small, usually direct, electric currents. Although the deflection of a galvanometer results from current in the moving coil, the voltage in a closed circuit producing this current is frequently the quantity of interest to the user. In this mode, galvanometers are used to detect a null or an unbalanced condition in a bridge or potentiometer circuit. Galvanometers have played a pivotal role in the evolution of electrical measurements but electronic instruments that employ amplifying circuits to achieve sensitivities approaching the nanovolt level are now more frequently used instead.