The LM318 is not a common component today. The circuit is suggested by National Semiconductor in its 1994 Linear Applications Handbook.
We have many versions of biofeedback with the 555 IC on this site. This is another one. We found it...
Using an operational amplifier of the time, this circuit was obtained from a 90s Radio...
This circuit was suggested by Popular Electronics from the 90s. The circuit is quite simple using...