This circuit can keep a set of lamps on for up to 1 minute, time given by C2 and R2 that can be changed. The load depends on the relay. The circuit is old, from 1988 documentation, but totally viable today.
This DC / DC converter was found in an American 1980s documentation. It provides a negative...
This low drift or offset circuit is from an 80's documentation. The configuration can be made with...
The integrated circuit used in this project is not common today, but it can be implemented with more...