Found in Ferranti's 1969 documentation, this circuit can be mounted with a modern equivalent transistor. The circuit has a 4 V immunity and can be used as a shield for sensors.
We found the configuration below, with unit gain, in the National Semiconductor Linear...
This circuit is from an Electronic Design from the 90's. The main integrated circuit is uncommon...
This circuit appears on this site from different sources. This is from documentation from the...