This simple sensitive circuit was suggested in a July 1992 Radio Electronics issue. The relay is a double-contact changeover relay. Sensitivity adjustment is made at R2.
This circuit is from a 1968 Electronic Design. The components are from the era and the operating...
This circuit was found in an Electronic Design from the 90s. The integrated circuit is from that...
This circuit, from a 1988 documentation, activates a relay for a period and has a touch shutdown as...