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 amplifier with a few watts of power was found in a Japanese technical documentation from the...
This high impedance headphone amplifier was found in American documentation from the 1990s. Any...
This small audio amplifier was found in the May 1994 issue of Electronics Now magazine. The power...