This circuit with the 555, was obtained in a 90s American documentation. The signal must be applied to a good amplifier. The sound is similar to that of a police siren.
Based on the Philips TDA3810N, this circuit was found in an 90s Electronics Now. The circuit has two...
This simple circuit does not use active components and uses a small speaker as a microphone. The...
This power amplifier configuration can be used in a public address system (ads) in the car. The...