Basic properties of harmonic oscillators on a torsional pendulum, specifically their free and driven oscillations. For the latter, the transient oscillations will be shown, before the steady state has been reached. The torsional pendulum consists of a circular copper ring with an eddy current brake, and a torsional spring. One end of the spring is attached to the copper ring, the other end to a motor via an eccentric-and-rod mechanism. For the experiment, another pendulum, also specifically designed for lecture demonstrations, will be used. It sits on an optical bench and is projected onto the front wall of the lecture hall, together with a meter indicating the exciting frequencies used for the driven oscillations. Two pointers, one attached to the pendulum, the other to the eccentric-and-rod mechanism used for moving the spring, allow observation of the phase difference between the exciting torque and the angular displacement of the pendulum.