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 obtained in a 1965 American magazine translation. The photocell can be the type...
This circuit was found in 1968 General Electric documentation. The circuit uses components from the era...
This circuit was found in a 1980s documentation, using a comparator from the time. The...