Rotary pendulum (Pohl’s pendulum)

This apparatus is used to investigate oscillation as damping is varied. Free, forced and chaotic oscillation may be generated. The resonator consists of a wheel with spokes, made of sheet copper and mounted on ball bearings, with a flat spiral spring. The resonator is excited by means of lever mechanics, using a drive motor connected to a cam. Rough or fine adjustment of motor speed is possible. Damping is provided by an eddy current brake. Surrounding the resonator is a scale shaped like a ring. Slits in the scale and pointers on the resonator and exciter lever can be used to project shadows for better visualising how the experiment works. Apparatus mounted on a base plate.
Motor power supply: 24 V DC, min. 600 mA
Damping unit power supply: 0-12V DC, continually variable
Dimensions: 400x140x270 mm