Found in a QST magazine from the 90s, this circuit broadcasts on different amateur radio bands depending on the coil. Data for the coil and crystal are provided next to the diagram.
Found in an Electronic Design from the 90's, this circuit supplies voltages according to the...
This simple two-transistor circuit used transistors from the 60s, having been found in a...
The circuit shown, found in French documentation from the 1970s, functions as a variable...