The circuit is from 1994 National Semiconductor documentation. The component is not easy to obtain, but there are equivalents that can be searched.
This circuit is from an Electronics Now, American magazine from December 1992. The magazine no...
We found this circuit in a 1983 English magazine, but it can be easily assembled with the BC548...
This simple alarm circuit was found in a 1998 documentation. When the sensors are activated, the...