In this experiment a rotating commutator alternately charges a capacitor and connects it to an inductance in series with a variable resistance. The output voltage across the capacitor is displayed on an oscilloscope. Since the commutator makes the pattern repetitive, it will remain on the face of the oscilloscope long enough to make measurements of the frequency and the damping. If a Ferrite rod is put inside one of the air coils, the increase in inductance will change the frequency, but not the damping. However, if a solid iron rod is put inside one of these coils, the eddy currents counteract the increase in the B field inside the iron and change the inductance very little. However, the eddy current losses greatly increase damping. A variety of condensers and air core inductances are supplied so that the oscillations can be studied for a variety of frequencies.