Found in a 1965 Electronic Design the purpose of this circuit is to control the gain of a stage by applying an external voltage. The circuit operates at high voltages.
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...