The operational amplifier used in this circuit is uncommon nowadays. We obtained this circuit from documentation from the 1980s, but it can be adapted to use more modern equivalents.
This alarm goes off if someone leaves a door open. We found it in the Encyclopedia of Electronic...
The pulse duration is determined by the 100k resistor and the separation by the 1M resistor. The...
This circuit uses high voltage transistors to provide direct power from the 110 V power grid or a...