Found in the July 1980 Radio Electronics magazine, this circuit uses an integrated circuit from the time and a power Darlington. The Darlington must be equipped with a heat sink.
This circuit can be used to recognize a tone by its frequency. When this tone is present in a...
We have many versions of biofeedback with the 555 IC on this site. This is another one. We found it...
In fact, it is a night light system that automatically turns on the outside lights when it gets...