This circuit was found in a 90’s EDN. The components used are still common and the sensors can have their quantity increased. The supply voltage is according to the relay.
This control, which may appear in other versions on this site, was found in documentation from the...
We found this circuit in a 1991 Hobbyst Electronics. The circuit makes use of an unusual...
This circuit turns a relay on or off by touching the sensors or by connecting sensors at these...