Alternating tone siren 555 (CB9202E)

Found in Radio Electronics from the 90s, this siren finds many variations on this site. The transistor must be equipped with a heat radiator.

| Clique na imagem para ampliar |

Timed Emergency Light (CB16507E)
We found this circuit in a 1998 documentation. The circuit can also be used as a minutery...
RF Oscillator (CB22259E)
This circuit supports several sets of coils and can oscillate from 1 to 44 MHz. The transistor is an old...
Remote Phone Ring (CB1349E )
This circuit, obtained in an old publication, causes a second telephone bell to be played in a...