A triple physical pendulum: an introduction to experiment

In this paper a description how to observe relative positions of triple pendulum links in order to investigate its kinematics is presented. An idea is focused on the design of a pendulum and then on how to put electronic elements into kinematical joints in order to carry out immediate measurement of an angle between two neighbouring links of the pendulum. Signals produced by electronic elements are first sent in by means of a radio method and then transmitted to crystal sets and other devices for their further analysis. An alternative proposal to apply an electronic circuit by connecting suitable filters in a series of three phase loops with low-pass filters added to them is also given.