This circuit was published in a 1979 magazine, but it can still be easily assembled as the components are common. The frequency between 50 Hz and 1.5 kHz is set in the VR1 potentiometer and the signal strength in VR2. Commercial values of 47k and 470 ohms can be used in practice. The signal is square, and the supply can be made with voltages from 5 to 12 V.
| Clique na imagem para ampliar |
