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 is the version of the previous circuit with shadow activation. The circuit can use relays from...
This 90's project shows how to use an old cassette recorder to practice telegraphy. In position A of the...
Using the 741 this basic circuit was found in the November 1973 Radio Electronics magazine. The...