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.
This transmitter was found in a 1993 documentation, but it can be assembled with operators like...
This transistor tester was found in a 1980 publication. The transistor can be the BC548 and the...
This circuit is from an Electronics Now from the 90s. The circuit uses a power integrated circuit...