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 timer was found in a 1994 Electronics Now. The relay must be a sensitive type. If it has a...
Published in the September 1973 issue of Radio Electronics magazine, this diagram may be useful to...
This circuit with 4 diodes was found in the July 1984 Radio Electronics magazine. The voltage of...