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 can modulate a laser rate at frequencies of 50 kHz. We found the old documentation. The bipolar...
To divide by an odd number‘ means not only the need for flip-flops, but some additional logic too. The...
The battery charger suggested in the figure has its current limited by resistor R1. This component may...