Ballistic galvanometer

Unlike a current-measuring galvanometer, the moving part has a large moment of inertia, thus giving it a long oscillation period.

For a regular galvanometer, the discharge time must be shorter than the natural period of oscillation of the mechanism.

The Grassot fluxmeter resolves this problem, by operating without any restoring force, making the oscillation period effectively infinite and thereby longer than any discharge time.

Its construction is similar to that of a ballistic galvanometer, but its coil is suspended without any restoring forces in the suspension thread or in the current leads.

When an electric charge is connected to the instrument, the coil starts moving in the magnetic field of the galvanometer's magnet, generating an opposing electromotive force and coming to a stop regardless of the time of the current flow.