This circuit that emits siren sound can be used in a fire alarm. We found it in an old American documentation. The signal must be applied to a good audio amplifier.
This circuit from a 2003 documentation, has a protection system that disarms the power supply if...
This circuit was obtained from an old American documentation, and practically any general-purpose transistor...
In the figure we have the circuit of a sweep generator obtained in an old publication. The central...