This circuit was found in a 1964 Electronic Design. The components are of the time, and modern equivalents can be used. Note the multi-emitter transistor.
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...