This circuit was found in a Radio Electronics Constructor, English magazine from April 1976; The magazine is no longer published, but the circuit can be easily assembled with BC558 transistors for TR1, 2N2646 for TR2 and BC548 for TR3. The frequency range is determined by the capacitor.

 

 


| Clique na imagem para ampliar |

 


| Clique na imagem para ampliar |