The theremin was invented by Russian physicist Lev Theremin in 1919 and became the first electronic musical instrument that had a career in the XX-century and it is still the only instrument which can be played without any mechanical touching. The theremin-player moves his hands near two antennas. The proximity of the right hand to the vertical antenna changes the electromagnetic field thus changing the pitch of the sound over a six- octave range. Left hand controls the volume. Theremins sound remembers sometimes the cello or violin, sometime the flute and often the human voice. The instruments circuit uses a beat frequency oscillator, in which an audible musical tone is derived from the beating between two high-frequency oscillators. The frequency of one of the oscillators is fixed. The frequency of the other is altered by the performers proximity to the pitch antenna.