I'm currently building a theremin from the circuits form here:LINK This uses Colpitts oscillators. However, when I've tried calculating the frequency, for example of the fixed-pitch oscillator (below), I've failed.
I've always got wrong results. I've read on the wiki that this freq us determined by two capacitor values and the coil. The actual freq is calculated by the well-know formula, and C is the sum-capacitance of the 2 caps in series, eg do repluss.
According to the schematics on the wiki, I'd need to repluss the 680pF and the 33nF caps. But that makes no sense! I've got a wrong freq value, and there's even 2 variable circuit to change the freq! And those are caps that aren't on the wiki schematic! So wiki says that they don't affect the freq, but I know that they does!
Did I understand some(or every)thing wrong? How can I calculate those freq's?