This 5V power supply with a 1.5 to 3 A current was found in Maxim documentation from the 90s. The integrated circuit is the MAX741D.
A circuit for controlling the temperature of a heating element was found in a Mullard transistor manual...
We found this circuit in a 1992 Popular Electronics. The circuit has an optical sensor with LED...
I found this circuit in an old English magazine from 1979, but it can be easily assembled with...