This tone control was obtained in the Audio Handbook of the National Semiconductor of 1977. The circuit controls the signals of medium frequencies in a wide dynamic range as shown in the diagram.
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...