This circuit was found in the August 1994 issue of Electronics Now magazine. The 4046 is uncommon these days and the frequency range is given by C1.
We find this circuit in a 1978 documentation. The circuit uses two inverters of a 4049 integrated...
For the 600 kHz range coil is formed by 35 turns of 28 AWG wire on a ferrite core with a diameter...
This circuit was found in Radio Electronics from the 90s. The CMOS integrated circuit is a PLL not...