The electrodynamic movement differs only slightly from the moving-coil movement: it has two coils
, a moving moving coil and a fixed field coil. In the electrodynamic movement, the magnetic field
is not generated by a permanent magnet, but by the current-carrying field coil. The moving rotary coil is located in this magnetic field. Thetorque is generated by the magnetic fields of both coils and is proportional to the product of
through both coils. If the current flow of the rotating coil (voltage coil) is derived from the applied voltage via a series resistor and the load current flows through the field coil (current coil), then power measurements can be carried out with such an arrangement. Electrodynamic measuring devices are used for active power measurements.