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.
This circuit can generate signals from 100 kHz to 1 MHz depending on the L1 coil. For the medium...
Using the LM383 this circuit was found in a Popular Electronics from the 90s. The source must be...
Found in an EDN from the 90's this circuit makes use of unusual components today. | Clique na...