The theremin (/ˈθɛrəmɪn/) is an early electronic musical instrument controlled without physical contact by the performer. Léon Theremin, a Russian inventor, patented it in 1928. The device was named after the inventor's name.


The instrument's controlling section usually consists of two metal antennas that sense the relative position of the thereminist's hands and control oscillators for frequency with one hand, and amplitude (volume) with the other. The electric signals from the theremin are amplified and sent to a loudspeaker.