This transmitter for the 3.5 and 7 MHz ham radio was found in a 1950s Japan publication. No information was given on the coils and the power supply.
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...