When pressing S1, S2 or S3 this circuit generates different tones for a tone-modulated remote-control system. The circuit also has a configuration that only powers the oscillator circuit when these switches are pressed. Each tone is adjusted independently in the corresponding trimpot. The tone output is applied to the transmitter which can also be powered by the same line that goes to pins 4 and 8 of the power 555. The circuit is from a book by Newton C. Braga published in the United States.
| Clique na imagem para ampliar |
