A moving coil galvanometer is an instrument used for detection and measurement of small electric currents. Principle A current carrying conductor placed in a magnetic field experiences a torque. See Animation
Ac changes its direction frequently and therefore the ordinary ammeter which is just a galvanometer with a shunt, tends to respond to the magnitude and direction of the instantaneous values of current and in effect it will not show any deflection. Ac is measured using hot wire ammeter, which is based on the heating effect … Continue reading Why ordinary ammeter cannot measure AC?