This alarm goes off if someone leaves a door open. We found it in the Encyclopedia of Electronic Circuits Volume 5 from 1995. The circuit uses components that are still common today.
This circuit was found in a 1965 Electronic Design. What it does is respond only to positive...
This car amplifier was found in the 1982 SGS Linear Integrated Circuits manual. The circuit can be...
This high input impedance circuit was found in American documentation from the 1980s. The power...