Theremin

Theremin Patented in 1928 by Leo Theremin, and commercially licensed by RCA that same year, the theremin uses an electronic oscillator as a stable reference tone of a very high frequency. It has another electronic oscillator, initially in tune with the reference, which has a variable frequency controlled by the proximity of the hand to a capacitive sensing element, usually an antenna of some sort. The difference between the two frequencies is a pitch in the audible range which is detected and…