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.
Found in Radio Electronics from the 90s, this circuit has a power given by the output amplifier. The...
This circuit was obtained in a 1982 English magazine. The purpose of this circuit is to interface...
We found this circuit in an English publication of 1976. It can be easily assembled by changing the...