This circuit was obtained from a 1980's QST magazine. The circuit can generate 1 to 15 MHz signals with 1 Vpp at 50 ohms load. Used transistors are still common today.
The note sequence for this circuit is achieved through integrated circuits controlled by the 555....
When a voice signal enters this circuit, the volume of the music being played automatically...
We found this configuration in a Radio Shack documentation from 1977. Here we have the way to...