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.
This metronome circuit was found in an American 1980s documentation. The circuit uses the 4001...
This circuit was found in Radio Electronics from July 1990. The circuit produces the sound of the...
Current sensors of the type High-Side (high side) are circuits that monitor the current drained by a...