This alarm siren circuit has a latch. We found it in an article in the January 1975 Radio Electronics magazine. Note the power given by Rx and the speaker. It can be increased by changing Q1.
We found this circuit in an old oscilloscope publication. With it, it is possible to observe the B...
We found this circuit in an Electronic Engineering from the 90s. It applies to any logical family....
This circuit is from a documentation for 1976 radio amateurs. We can implement this circuit with...