This timing circuit was found in old documentation. The technology is CMOS. The supply can be made with voltages from 3 to 12 V. The time depends on R1 and C1.
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...