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.
We found this circuit in the March 1976 Radio Electronics magazine. The circuit is very...
This high impedance step suggested by an English publication can operate up to 1 MHz with 1 V rms...
This circuit found in an American documentation from 1964, alters the duration of a pulse and can...