We found this circuit in a 1980s documentation. Equivalent components can be used. The circuit senses temperatures in the range of 0 to 50º C and uses a transistor as sensor.
We found this circuit in a Popular Electronics of the 90s. The MOSFET can be of any type,...
Found in a 1970s RCA documentation, this circuit uses a relay to control external loads. R1 is 150...
This circuit was obtained in the publication 101 Electronics Projects of 1979. The circuit can be...