This semi-proportional temperature control was found in old American documentation. The components are from the period and the maximum power of 2.4 kW.
This circuit was obtained in a Motorola manual, but it applies to almost any operational...
Found in a 1970 EEE this circuit emulates a zener diode whose voltage can be set to R2. Power...
This circuit different from the timer was found in an English publication from 1978. The circuit uses...