I’m working on a design that uses a common Colpitts oscillator as a base. As in the following example:The Best Electronics Tutorial for Colpitts Oscillator
It works, but I’m stumped as to how to figure out the values of the various components. I’ve run multiple simulations and have a document with numbers and results, but I’m still unsure how to choose the two Cs for the LC tank. The oscillation does not start or is distorted if the values are not adequately matched to those of the coil (even if the relationship between Cs is roughly 10). I’ve been looking for a direct response to this query, but there aren’t any conclusive answers in the forum, despite a few posts on the subject.
I know F= 1/(2pi sqrt(LC)) but I suppose that you can’t make a 5 Mhz oscillator with a mH coil and pF coils or a 5Khz with 1uH coil and 1000uF capacitors (aproximate values).
I’m not sure, but I think that everything has to do with the impedances of the components. The impedances should be matched to the amplifier in and out resistances in any way. Perhaps it’s a problem with common-base amplifiers.