This circuit was found in Signetics documentation from the 90's. The circuit performance curve is shown next to the diagram. The sensor is an NTC.
This circuit with common CMOS components was found in the November 1984 issue of Radio Electronics...
This is the power step of the previous circuit. Output transistors must be mounted on good heat...
In the figure we show how to expand the count from 26 to 32 with 4017 CMOS integrated circuits. The...