This circuit is from a Radio Electronics from October 1963. The transistor is a power transistor of the time, and two transformers are used. The input has 10k impedance and is powered by 12 V.
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...