This guitar effect circuit was found in a 2002 documentation. The circuit can be powered by a 9 V battery as it has low consumption. The connections of the input and output audio signals must be shielded.
We found this simple alarm circuit in a 1986 documentation. The circuit uses sensors of the NA...
This sound relay or Vox was found in 70s RCA documentation. SCRs can be common types today and...
Placed near a common receiver, this oscillator is intended to generate a beating signal to receive...