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.
The 556 consists of a double integrated circuit 555, which can be replaced by them in this...
We found this circuit in a Radio Electronics from January 1967. The SCR is already the C106, which...
This circuit is from American documentation from 1970. It can be designed with a BC558 and for the...