We found this code key or coded keyboard in a publication from the 90s. The circuit uses components that are still common today and is powered by a 12 V voltage according to the relay used.
This modulator circuit was found in an American documentation from the 90's. The circuit uses a...
The integrated circuit used in this 1982 project is not very common today. It can be adapted to...
We found this circuit in a 1993 documentation. It is a high input resistance millivolimeter whose...