Open.Theremin.RC Schematic

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The present theremin, like the original one, consists of two resonators. The reference oscillator using a 16MHz quartz to produce a fixed frequency of 125kHz. The variable oscillator, built with a VCO, produces a frequency that can be influenced by the hand near the antenna. The mixer (a simple XNOR) provides the difference of the two frequencies that is then filtered and made audible by the TL072.