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 found in documentation two years 80. Transistors can be modern equivalents. Or...
This circuit, very critical due to the frequency at which it operates, was found in an American...
This stereo circuit with the 2002 integrated circuit. The power is 6 W per channel with 16 V of...