Opto control for triac (CB20552E)

Found a documentation for PC from 1992, this circuit is indicated for the English power grid of 240 V.

Temperature measurement interface (CB9598E)
We found this circuit in a documentation from the 90's. Information on the A/D converter was not...
Transistor Test (CB12379E)
This simple test for general purpose NPN and PNP transistors was found in a 1974 publication....
Precision analog multiplier (CB7393E)
Found in Linear Technology documentation from the 1980s, this circuit has an accuracy of 0.01%....