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.
The more sensitive the instrument used the better the sensitivity of the indicated meter. We...
Based on the 4017 integrated circuit, this circuit of a European 303 Circuits from the 90s,...
The integrated circuit used in this project is unusual and it includes internal transistors that...