Found in Ferranti's 1968 documentation, this circuit uses a Darlington photo transistor to drive a 12V relay. The circuit can be implemented with modern equivalent components.
We found this circuit with very high input resistance in an old documentation. The circuit is still...
The figure shows how to implement a conventional current monitor with differential amplifier on an H...
We find this circuit in the 80's own component manual itself. The characteristics of the circuit...