This circuit has a sensitivity of 2uW. We found it in documentation from the 1980s. The integrated circuit is from that time. Equivalents can be tried.
This circuit was found in a 1993 publication. The L1 coil consists of 12 turns in a ferrite core...
This moisture-activated relay was obtained from an American documentation from the 1980s,...
The integrated circuit used in this project is unusual. We found this configuration in Motorola's Linear...