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.
We found this circuit in an old neon lamp application manual. The circuit stores a call. The...
Poptronics recommends this circuit for use in the car when the headlights are left on. The circuit...
We found this circuit in a 1981 publication, when it was still possible to find 22.5 V batteries (used...