This apparatus is an improvement over the conventional apparatus to show the effects of vibrations in a stretched cord and examine the relationship between frequency, tension and density.
A thin steel rod is clamped near one end through two 4 mm socket terminals. This rod passes through the centre of a small solenoid and between the poles of a magnet.
Adjustable contact points fitted through a second pair of 4 mm socket terminals make alternating connection with an adjustable contact on the rod. The rod has a small hole at one end for the attachment of thread which passes over a pulley mounted on a bench clamp and supports a scale pan, 75 mm diameter, supplied complete with pulley with clamp and scale pan, 2V A.C. power supply