Found in a 73 magazine from the 1980s, this circuit generates signals from 3.2 to 22 MHz. FETs can be general-0purpose current types. No information about the coils is given.
This circuit was found in an English magazine Radio & Electronics Constructor of February 1977....
This circuit was found in an American publication from the 70s, but it can be assembled with more...
This microphone circuit was found in a collection of American 80's layouts, using operational...