Forced oscillations. (Student experiment)

One of the most attractive experiments with forced oscillations was described by Burchell (1975). He describes measurement of the logarithmic decrement as a function of damping, and of the amplitude of forced vibrations as a function of damping and of frequency. However, in common with most descriptions of mechanical systems, the examination of the phase relationship is very sketchy indeed. The present author describes a technique to simplify the measurement of the phase angle and so add to the completeness of a truly elegant experiment.