The capacitive voltage -divider network, which happens to be produced up of C1 and C2, is successfully shunted through the crystal XTAL1 and functions as being the feedback network that triggers the circuit to oscillate. When an electrical voltage is placed on a quartz crystal, it bodily deforms or vibrates. https://fernandozyvdj.ampblogs.com/not-known-facts-about-timing-components-for-consumer-electronics-71670932