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.
The LDO series (Low Dropout) TPS80 from Texas Instruments (www.ti.com) can provide output voltages...
Suggested by an American publication, this circuit has 5 operating conditions indicated in the...
Found in a documentation from the 70s, this circuit can be implemented today with ease. The relay...