This simple three-LED sensor uses an NTC at the input. The circuit is based on an uncommon integrated component today. We found it in documentation from the 80s.
We found this circuit in an old publication. The components used are rare today. Accuracy depends on...
This TTL circuit has a well-known configuration, having been found in a Radio Electronics magazine...
The circuit shown in the figure was suggested by National Semiconductor in its 1994 Linear...