21.20(a) is usually called the Pierce crystal. The resulting circuit frequency of oscillations is set via the collection resonant frequency of your crystal. Variants in offer voltage, transistor parameters, and many others. don't have any impact on the circuit working frequency which can be held stabilized through the crystal. The https://milownduk.ageeksblog.com/33795691/everything-about-timing-components-for-consumer-electronics