21.twenty(a) is normally known as the Pierce crystal. The ensuing circuit frequency of oscillations is about with the sequence resonant frequency on the crystal. Versions in offer voltage, transistor parameters, and so forth. don't have any effect on the circuit operating frequency that is held stabilized by the crystal. The https://crystal-oscillator26047.pointblog.net/the-smart-trick-of-consumer-electronics-crystal-oscillators-that-nobody-is-discussing-79553461