This circuit was found in a 1977 documentation. With it we have the direct indication, through LEDs of an ASCII signal. The circuit must be powered by a voltage of 5 V.
The integrated circuit used in this project is not common today, but it can be implemented with more...
Found in an American publication from 1969, this circuit can be adapted to be used as a shield....
This current meter with many scales was found in a 80s American documentation. The operational amplifier...