The integrated circuit used in this 2002 project is not very common. It is powered directly by the telephone line, requiring no power supply.
The circuit shown in the figure on the right can be used on a data transfer bus with the use of an...
This timer was found in Japanese documentation from the 1960s. The transistor can be replaced by...
We found this circuit in a documentation from the 90's. The circuit can be assembled with 741...