Found in a 90s R-E Experimenter Handbook, this circuit has a greater gain than the previous one for presenting two stages. The integrated circuit used is uncommon today.
In the waiting condition, the consumption of this alarm is extremely low, of the order of...
This is a project from a 1987 publication. The circuit tests transistors without removing them...
This sensitive motion sensor with inductive sensor was found in a 90s Elektor. The circuit uses only...