We found this circuit in an English publication from the 60's. The transistors are of germanium of the time and the headphones must be high impedance magnetic.
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...