Theremin Prague Museum of Music – Capacitors!

Theremin Prague Museum of Music

The theremin was the product of Soviet government-sponsored research into proximity sensors. The instrument was invented by a young Russian physicist named Lev Sergeyevich Termen (known in the West as Léon Theremin) in October 1920 after the outbreak of the Russian Civil War. After a lengthy tour of Europe, during which time he demonstrated his invention to packed houses, Theremin moved to the United States, where he patented his invention in 1928. Subsequently, Theremin granted commercial production rights to RCA.

During the 1930s, Lucie Bigelow Rosen was also taken with the theremin and together with her husband Walter Bigelow Rosen provided both financial and artistic support to the development and popularisation of the instrument.

In 1938, Theremin left the United States, though the circumstances related to his departure are in dispute. Many accounts claim he was taken from his New York City apartment by NKVD agents (preceding the KGB), taken back to the Soviet Union and made to work in a sharashka laboratory prison camp at Magadan, Siberia. He reappeared 30 years later. In his 2000 biography of the inventor, Theremin: Ether Music and EspionageAlbert Glinsky suggested the Russian had fled to escape crushing personal debts, and was then caught up in Stalin’s political purges. In any case, Theremin did not return to the United States until 1991.


The theremin is distinguished among musical instruments in that it is played without physical contact. The thereminist stands in front of the instrument and moves his or her hands in the proximity of two metal antennas. The distance from one antenna determines frequency (pitch), and the distance from the other controls amplitude (volume). Higher notes are played by moving the hand closer to the pitch antenna. Louder notes are played by moving the hand away from the volume antenna.

Most frequently, the right hand controls the pitch and the left controls the volume, although some performers reverse this arrangement. Some low-cost theremins use a conventional, knob operated volume control and have only the pitch antenna. While commonly called antennas, they are not used for receiving or broadcasting radio waves, but act as plates of capacitors.

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