We have many versions of biofeedback with the 555 IC on this site. This is another one. We found it in October 1986 Radio Radio Electronics magazine. The power supply must be isolated.
This circuit was obtained in a magazine Hands On-Electronics from June 1987. It is a circuit that...
This is the receiver for the previous circuit. The audio amplifier supports equivalents. The...
This distortion circuit was found in an American publication from 1970. It can be assembled with...