This circuit is from an American 1964 documentation. Transistors of the time are used, but modern equivalents can be employed.
In the figure we have a security system consisting of a sophisticated alarm found in a 90s edition...
The purpose of this circuit found in an American 1980s documentation is to produce a current pulse to...
The transistor used in this circuit is uncommon today. AC124 or equivalent such as AC188K and...