This frequency triple oscillator circuit was found in an American publication in 1967. The FET is current and more detailed information about the coils is not given.
This circuit was found in a Dutch documentation from 1970. The circuit makes use of semiconductors that...
I found this circuit in an English magazine from July 1982. The circuit is still viable because all...
In the figure we have a sensor circuit that makes use of common transistors and a photo diode as...