This circuit is from an American 80's documentation. The integrated circuit is from the time and the sensor consists of a smoke chamber measuring its transparency change.
A binary counter until 2" or a divide-by-the same value can be built by cascading n 4013...
Coupled to a bell, this year 2000 circuit provides an indication for attendance, if the person is...
This circuit appears elsewhere in this section, obtained from other documentation. The circuit is for...