Siren in a box (CB7093E)

Found in Elementary Electronics from 1970, this circuit is a toy for generating different types of sound effects. The circuit is battery powered.

| Clique na imagem para ampliar |

Delayed SCR trigger (CB19336E)
The circuit shown is from an old European publication. In it we have the way to activate a relay...
Audio Line Amplifier (CB4769E)
We found this circuit in a European publication from the 1990s. Transistors are still common types...
Active three-tone filter (CB20808E)
This circuit was found in an American documentation and can be added to common amplifiers of any...