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.
This circuit for frequencies of 20 to 2 kHz was obtained in English documentation from 1966. The...
Indicated for adjustment in transmitters for the 11-meter band, this circuit with analog meter was...
The circuit shown uses the LM340 but applies to other regulators. We found this setting in...