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 16-second voice recording circuit was featured in a telephone answering machine circuit in...
This circuit is from the Motorola LinearDatabook of 1990. It shows how it uses the LF355, 356 and...
This simple circuit presents a voltage gain of about 1,500. The input impedance is high and the...