This circuit was found in a 1966 General Electric documentation. It makes use of direct contact water sensors and therefore requires an isolation or low voltage relay drive transformer.
Although it is a common configuration today, this circuit was taken from an old publication. The...
This circuit was found in an old publication from 1989 but can still be assembled today with BD135...
This circuit was suggested by Popular Elecronics from the 90's. The circuit has high input...