This simple unijunction and bipolar generator appeared in Radio Electronics magazine in September 1865. It generates signals from 100 kHz to 60 MHz and is powered by two 9 V batteries.
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...