This circuit is from a 1968 documentation. It makes use of thermistors (NTC) to indicate overheating of charged batteries. Modern equivalent components can be used.
We found this circuit in the August 1994 issue of Electronics Now. The 4046 is unusual today. The...
This signal conditioner humidity sensor was found in a 1980s Linear Technology documentation. The circuit...
The battery is charged by the photocell that keeps the low consumption beacon in the dark. The...