We found this multiple thermostat circuit in July 1980 Radio Electronics magazine. It uses opto-triacs for power control and operates on a 117 VAC mains.
The presented circuit has compensation for cold junction. In addition to a voltage reference, it...
This “people detector” with pyroelectric sensor was found in the April 1991 issue of Radio...
This circuit from a 1988 documentation uses an NTC sensor to keep a greenhouse temperature...