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 is from an article in the December 1988 issue of Radio Electronics magazine that...
This circuit was found in an American documentation from the 80's. The sensor is a special...
The FET can be a BF245, and the other transistors can be the BC548 and BC558 in this simple AM...