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 have many versions of biofeedback with the 555 IC on this site. This is another one. We found it...
This instrumentation amplifier with differential inputs was found in documentation from the 90s....
Found in an old Popular Electronics, this circuit warns when a remote lighting system is not...