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 circuit is from 1994 documentation by National Semiconductor. What it does is convert the...
This circuit with the known PLL 567 can be found in other versions in this section and in this...
This sophisticated circuit of the coin-toss game was found in an American 1980s documentation. The circuit...