This old circuit from the 80's generates logic signals with 50% active cycle (squares). The integrated circuit used is not common today, but equivalent logic functions can be used in a modern version.
This circuit causes the relay to be energized when the input voltage exceeds the voltage value of...
The maximum frequency of this circuit is 500 kHz. We found it in a documentation for radio...
The mains cables work as antennas. We can take advantage of them with this circuit that consists of a...