This circuit was found in an 80s Hands On Electronics. It senses the water level in a reservoir by driving a pump when needed.
We found this circuit in a Poptronics from 1998. The circuit can be extended to more competitors...
We found this circuit in documentation from the National Semiconductor of the 1980s. The circuit...
A configuration like the one used with the 4013 is also suitable for the 4027. The amount of time...