This simple Morse Code oscillator was found in a 1980s American documentation. The power supply should be powered with 5V and the integrated can be the 7400.
This circuit is as shown in a 1976 technical documentation. It can currently be assembled with any...
Equivalent transistors, like the BC548 and BC558 pair can be used in this circuit that we find in an...
This circuit, from the On Semiconductor thyristor manual, is suitable for incandescent lamps or...