PHYSICS OF THE THEREMIN

We discuss some of the interesting physics behind the design and opera tion of the Theremin electronic musical instrument. To complement the theory we present details of a parallel effort to construct two versio ns of this remarkable instrument. One of these designs remains fairly faithful to the traditional beat frequency oscillator approach that fi rst inspired Theremin's invention, while the other contains more moder n electronics that helps make more reliable the setting up and use of the instrument. The emphasis on the physical principles continues into a comparison of the two instruments. Following completion, the Therem ins have been extensively used in public and schools science exhibitio ns and in lecture demonstrations. (C) 1998 American Association of Phy sics Teachers.