The CMOS 4060 integrated circuit consists of a frequency divider counter with internal elements already incorporated for the elaboration of an external oscillator, both RC type and crystal controlled. In the figure we show how to implement a crystal oscillator with frequencies up to about 4 MHz using this component. We observe that the maximum frequency depends on the supply voltage, so the 4 MHz will only be reached with a supply higher than 9 V. The trimmer adjusts the ideal oscillation point so that the circuit is initialized when the power is turned on. This is achieved by compensating for the internal capacitances of the crystal. Remember that the signal obtained at the output of this circuit is rectangular.
