This configuration with the LM111 was found in your factory manual. The circuit can be implemented with modern operational equivalents. The power supply must be symmetrical.
With this circuit, from an American documentation from 1976, it is possible to measure...
We found this circuit in an old RCA publication. The components are of the time, admitting...
This circuit emits an audible signal when the mains voltage ceases. The circuit is from a 1973...