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 originally intended for reading movie soundtracks. The circuit is from 1967 and...
This circuit is from an Italian magazine Elettronica 2000 of September 1987. It is a pulsator for...
Published in a February 1978 Radio Electronics magazine article, this digital circuit uses some of...