The apparatus originally designed
to show the effects of vibrations in a stretched cord and investigate the
relationship between frequency tension and density. in addition the
provision of electrical contacts opened and closed by the vibrating armature
allow the apparatus to be used as high speed change over switch in for e.g..
capacitor charge/discharge exp. comprises a thin steel rod armature mounted
in a clamp formed by a pair of 4 mm socket terminals so that its free length
may be adjustable as desired . the complete apparatus is carried upon a box
type base 150 x 80 mm.