General Electric suggests this circuit in a 1980s documentation. The operational of the time is FET-type input. Modern equivalents may be used.
This simple rain, leak or moisture detector circuit appears in other places on this site with...
This circuit was obtained in a 90s EDN. The components used are from that time. The voltage...
This circuit is from a 1967 General Electric SCR manual. The capacitors are polyester and the...