This circuit operates from 25 to 65 kHz depending on the transducer used and the settings. We found it in the Radio Electronics magazine of July 1985. The 9V to 12V power supply is not given.
This circuit, found in a 1985 documentation, causes two incandescent lamps to flash alternately. The...
This circuit produces signals in the range of 200 Hz to 2 kHz. We found it in the magazine...
This circuit operates at a voltage of 1.3 V from a single mercury cell. We found in an old...