Found in an English publication from the 1980s, this circuit can be built with equivalent transistors such as the BC549. The signal must be applied to an external amplifier.
This QST circuit generates 4 frequency signals according to the crystals used. Transistors admit...
This circuit generates signals from 0.01 Hz to 10 kHz, but uses unusual components today. The...
This dimmer or light control for incandescent light bulbs or even small heaters, is one of many...