Galvanometer
![An early D'Arsonval galvanometer showing magnet and rotating coil.](/Images/godic/202412/22/A_moving_coil_galvanometer._Wellcome_M00163974541.jpg")
![Diagram of D'Arsonval/Weston type galvanometer. As the current flows from + through the coil (the orange part) to −, a magnetic field is generated in the coil. This field is counteracted by the permanent magnet and forces the coil to twist, moving the pointer, in relation to the field's strength caused by the flow of current.](/Images/godic/202412/22/Galvanometer_scheme.svg4541.png")
![Modern closed-loop galvanometer-driven laser scanning mirror from Scanlab.](/Images/godic/202412/22/DynAXIS_L4541.jpg")
![A galvanometer mechanism (center part), used in an automatic exposure unit of an 8 mm film camera, together with a photoresistor (seen in the hole on top of the leftpart).](/Images/godic/202412/22/Autoexpmeter4541.JPG")
A galvanometer is an electromechanical instrument for detecting and measuring electric current. The most common use of galvanometers was as analog measuring instruments, called ammeters, used to measure the direct current (flow of electric charge) through an electric circuit. A galvanometer works as an actuator, by producing a rotary deflection (of a "pointer"), in response to electric current flowing through a coil in a constant magnetic field.