The oscillating system of the torsional pendulum consists of a copper wheel mounted on a ball bearing which is excited to harmonic oscillations by means of a motor and a spiral spring. The natural frequency of the wheel is about 0.5 Hz. The motor frequency can be continuously adjusted between standstill and approximately 3 Hz. The wheel has markings on its periphery, with which the amplitude can be read from a scale surrounding the wheel. The damping of the oscillating system can be varied over a large range by means of an electromagnet. This apparatus can perform: Determination of the frequency of a free-damped oscillation. Observation of the consecutive amplitudes of a free-damped oscillation. A periodic and creeping adjustment of zero point of a free damped oscillation with appropriately adjusted damping. Forced oscillations and their resonance characteristics at different dampings. Phase shift between exciter and resonator and others.