This variable frequency (VFO) oscillator was found in a Japanese publication of 1962. Coil details (in Japanese, but can be deduced) are next to the diagram covering the 3.5 MHz band.
This circuit found in a 1988 documentation consists of a timer or sequential timer controller. The...
This resistance meter circuit was found in the February 1984 issue of Radio Electronics magazine. It is...
We found this circuit on the internet. The components are current, and the time depends on C1...