This circuit from a 1967 documentation generates 2.5 Hz signals depending on the capacitors used, in this case 160 uF. For 4 6700 pF the signal will be 20 kHz.
Found in a 1960 Sylvania manual, this circuit can be implemented with a modern equivalent...
This configuration, already presented in other points of this section and website, is of a...
We found this precise crystal oscillator for the 144 MHz band, depending on the crystal used. The...