Delzenne’s circle by max kohl, c 1910
On application
A max kohl earth inductor or delzenne circle is a flip coil used to measure the magnitude and direction of the earth’s magnetic field. The rotating coil is quickly flipped through 180 degrees, and the output is fed to a ballistic galvanometer. This device, with a long period of oscillation, measures the total charge delivered by the induced emf; the charge is then proportional to the magnitude of the magnetic field threading the coil.
