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.
July 2017 - The Texas Instruments TAS5782M Closed Feedback- Class D Amplfier Evaluation Module can now...
This circuit can be controlled by pin 1 through the output of a microcontroller functioning as a...
Found in a documentation for radio amateurs from the 90s, this circuit is suitable for RF...