This circuit was found in the Electronics Experimenter Handbook of 1961. The circuit uses door sensors and others. It is powered by 12 V from the car battery.
I found this circuit in a Popular Electronics from November 1999. The magazine is no longer...
This circuit of a 1991 PE Hobbyst Handbook allows the brightness of the incandescent lamp to be...
This simple operational amplifier tester was published in the November 1987 issue of Radio...