This circuit has 4 operating modes and was found in the 1995 Encyclopedia of Electronic Circuits Volume 5. The circuit works with light or heat sensors.
The integrated circuit can be replaced by more modern operational amplifiers like the 741. The...
We found this circuit in the August 1970 issue of Radio Elecronics magazine. It uses the CA3018...
The configuration shown in the figure is quite simple and can be used to activate a signaling LED...